21647996 has 12 divisors (see below), whose sum is σ = 37923648. Its totient is φ = 10812672.

The previous prime is 21647993. The next prime is 21648001. The reversal of 21647996 is 69974612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21647993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2645 + ... + 7091.

It is an arithmetic number, because the mean of its divisors is an integer number (3160304).

Almost surely, 2^21647996 is an apocalyptic number.

It is an amenable number.

21647996 is a deficient number, since it is larger than the sum of its proper divisors (16275652).

21647996 is a wasteful number, since it uses less digits than its factorization.

21647996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5668 (or 5666 counting only the distinct ones).

The product of its digits is 163296, while the sum is 44.

The square root of 21647996 is about 4652.7406976964. The cubic root of 21647996 is about 278.7014530670.

The spelling of 21647996 in words is "twenty-one million, six hundred forty-seven thousand, nine hundred ninety-six".