21768885 has 32 divisors (see below), whose sum is σ = 39070080. Its totient is φ = 11499264.

The previous prime is 21768883. The next prime is 21768893. The reversal of 21768885 is 58886712.

It is not a de Polignac number, because 21768885 - 2¹ = 21768883 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21768885.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21768883) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14542 + ... + 15968.

It is an arithmetic number, because the mean of its divisors is an integer number (1220940).

Almost surely, 2^21768885 is an apocalyptic number.

It is an amenable number.

21768885 is a deficient number, since it is larger than the sum of its proper divisors (17301195).

21768885 is a wasteful number, since it uses less digits than its factorization.

21768885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1554 (or 1548 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The square root of 21768885 is about 4665.7137717610. The cubic root of 21768885 is about 279.2192749547.

The spelling of 21768885 in words is "twenty-one million, seven hundred sixty-eight thousand, eight hundred eighty-five".