21880815165 has 48 divisors (see below), whose sum is σ = 41394188160. Its totient is φ = 10603866240.

The previous prime is 21880815109. The next prime is 21880815167. The reversal of 21880815165 is 56151808812.

It is not a de Polignac number, because 21880815165 - 2¹⁴ = 21880798781 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 21880815165.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21880815167) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1173304 + ... + 1191806.

It is an arithmetic number, because the mean of its divisors is an integer number (862378920).

Almost surely, 2^21880815165 is an apocalyptic number.

It is an amenable number.

21880815165 is a deficient number, since it is larger than the sum of its proper divisors (19513372995).

21880815165 is a wasteful number, since it uses less digits than its factorization.

21880815165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20914 (or 20911 counting only the distinct ones).

The product of its (nonzero) digits is 153600, while the sum is 45.

The spelling of 21880815165 in words is "twenty-one billion, eight hundred eighty million, eight hundred fifteen thousand, one hundred sixty-five".