21612396 has 36 divisors (see below), whose sum is σ = 54611592. Its totient is φ = 6649344.

The previous prime is 21612379. The next prime is 21612397. The reversal of 21612396 is 69321612.

It is not an unprimeable number, because it can be changed into a prime (21612397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3301 + ... + 7356.

Almost surely, 2^21612396 is an apocalyptic number.

21612396 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21612396 is an abundant number, since it is smaller than the sum of its proper divisors (32999196).

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

21612396 is a wasteful number, since it uses less digits than its factorization.

21612396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10690 (or 10675 counting only the distinct ones).

The product of its digits is 3888, while the sum is 30.

The square root of 21612396 is about 4648.9134214352. The cubic root of 21612396 is about 278.5485949538.

The spelling of 21612396 in words is "twenty-one million, six hundred twelve thousand, three hundred ninety-six".