21223146 has 16 divisors (see below), whose sum is σ = 48510144. Its totient is φ = 6063744.

The previous prime is 21223141. The next prime is 21223159. The reversal of 21223146 is 64132212.

It is a super-2 number, since 2×21223146² = 900843852274632, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21223141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 252615 + ... + 252698.

It is an arithmetic number, because the mean of its divisors is an integer number (3031884).

Almost surely, 2^21223146 is an apocalyptic number.

21223146 is an abundant number, since it is smaller than the sum of its proper divisors (27286998).

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

21223146 is a wasteful number, since it uses less digits than its factorization.

21223146 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 505325.

The product of its digits is 576, while the sum is 21.

The square root of 21223146 is about 4606.8585825918. The cubic root of 21223146 is about 276.8661875897.

Adding to 21223146 its reverse (64132212), we get a palindrome (85355358).

The spelling of 21223146 in words is "twenty-one million, two hundred twenty-three thousand, one hundred forty-six".