21162645 has 72 divisors (see below), whose sum is σ = 44169216. Its totient is φ = 9180864.

The previous prime is 21162641. The next prime is 21162653. The reversal of 21162645 is 54626112.

21162645 is a `hidden beast` number, since 2 + 1 + 16 + 2 + 645 = 666.

It is not a de Polignac number, because 21162645 - 2² = 21162641 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21162641) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 166572 + ... + 166698.

Almost surely, 2^21162645 is an apocalyptic number.

It is an amenable number.

21162645 is an abundant number, since it is smaller than the sum of its proper divisors (23006571).

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

21162645 is a wasteful number, since it uses less digits than its factorization.

21162645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191 (or 165 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 21162645 is about 4600.2874910162. The cubic root of 21162645 is about 276.6028489440.

Adding to 21162645 its reverse (54626112), we get a palindrome (75788757).

It can be divided in two parts, 2116 and 2645, that added together give a square (4761 = 69²).

The spelling of 21162645 in words is "twenty-one million, one hundred sixty-two thousand, six hundred forty-five".