21645896 has 16 divisors (see below), whose sum is σ = 42973740. Its totient is φ = 10186240.

The previous prime is 21645881. The next prime is 21645901. The reversal of 21645896 is 69854612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18369796 + 3276100 = 4286^2 + 1810^2 .

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, 79445 + ... + 79716.

Almost surely, 2^21645896 is an apocalyptic number.

It is an amenable number.

21645896 is a deficient number, since it is larger than the sum of its proper divisors (21327844).

21645896 is a wasteful number, since it uses less digits than its factorization.

21645896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159184 (or 159180 counting only the distinct ones).

The product of its digits is 103680, while the sum is 41.

The square root of 21645896 is about 4652.5150187829. The cubic root of 21645896 is about 278.6924408090.

The spelling of 21645896 in words is "twenty-one million, six hundred forty-five thousand, eight hundred ninety-six".