21180075918 has 64 divisors (see below), whose sum is σ = 44591219712. Its totient is φ = 6693857280.

The previous prime is 21180075913. The next prime is 21180075919. The reversal of 21180075918 is 81957008112.

It is a self number, because there is not a number n which added to its sum of digits gives 21180075918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21180075913) 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, 8281896 + ... + 8284452.

It is an arithmetic number, because the mean of its divisors is an integer number (696737808).

Almost surely, 2^21180075918 is an apocalyptic number.

21180075918 is an abundant number, since it is smaller than the sum of its proper divisors (23411143794).

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

21180075918 is a wasteful number, since it uses less digits than its factorization.

21180075918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3089.

The product of its (nonzero) digits is 40320, while the sum is 42.

The spelling of 21180075918 in words is "twenty-one billion, one hundred eighty million, seventy-five thousand, nine hundred eighteen".