21026412 has 72 divisors (see below), whose sum is σ = 59956400. Its totient is φ = 6367680.

The previous prime is 21026389. The next prime is 21026419. The reversal of 21026412 is 21462012.

21026412 is a `hidden beast` number, since 21 + 0 + 2 + 641 + 2 = 666.

It is a super-2 number, since 2×21026412² = 884220003187488, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21026419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12264 + ... + 13872.

Almost surely, 2^21026412 is an apocalyptic number.

21026412 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21026412, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29978200).

21026412 is an abundant number, since it is smaller than the sum of its proper divisors (38929988).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21026412 is a wasteful number, since it uses less digits than its factorization.

21026412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1644 (or 1625 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21026412 is about 4585.4565748680. The cubic root of 21026412 is about 276.0080337926.

Adding to 21026412 its reverse (21462012), we get a palindrome (42488424).

Subtracting 21026412 from its reverse (21462012), we obtain a square (435600 = 660²).

It can be divided in two parts, 210264 and 12, that added together give a triangular number (210276 = T₆₄₈).

The spelling of 21026412 in words is "twenty-one million, twenty-six thousand, four hundred twelve".