21326020 has 48 divisors (see below), whose sum is σ = 46992960. Its totient is φ = 8118656.

The previous prime is 21326017. The next prime is 21326021. The reversal of 21326020 is 2062312.

It is a junction number, because it is equal to n+sod(n) for n = 21325985 and 21326003.

It is not an unprimeable number, because it can be changed into a prime (21326021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47919 + ... + 48361.

It is an arithmetic number, because the mean of its divisors is an integer number (979020).

Almost surely, 2^21326020 is an apocalyptic number.

21326020 is a gapful number since it is divisible by the number (20) 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 21326020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23496480).

21326020 is an abundant number, since it is smaller than the sum of its proper divisors (25666940).

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

21326020 is a wasteful number, since it uses less digits than its factorization.

21326020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 564 (or 562 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21326020 is about 4618.0103940983. The cubic root of 21326020 is about 277.3128137298.

Adding to 21326020 its reverse (2062312), we get a palindrome (23388332).

It can be divided in two parts, 21 and 326020, that added together give a square (326041 = 571²).

The spelling of 21326020 in words is "twenty-one million, three hundred twenty-six thousand, twenty".