21642996 has 12 divisors (see below), whose sum is σ = 50500352. Its totient is φ = 7214328.

The previous prime is 21642979. The next prime is 21643009. The reversal of 21642996 is 69924612.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 901780 + ... + 901803.

Almost surely, 2^21642996 is an apocalyptic number.

It is an amenable number.

21642996 is an abundant number, since it is smaller than the sum of its proper divisors (28857356).

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

21642996 is a wasteful number, since it uses less digits than its factorization.

21642996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1803590 (or 1803588 counting only the distinct ones).

The product of its digits is 46656, while the sum is 39.

The square root of 21642996 is about 4652.2033489520. The cubic root of 21642996 is about 278.6799943515.

The spelling of 21642996 in words is "twenty-one million, six hundred forty-two thousand, nine hundred ninety-six".