21116172372 has 12 divisors (see below), whose sum is σ = 49271068896. Its totient is φ = 7038724120.

The previous prime is 21116172353. The next prime is 21116172397. The reversal of 21116172372 is 27327161112.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21116172372² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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, 879840504 + ... + 879840527.

It is an arithmetic number, because the mean of its divisors is an integer number (4105922408).

Almost surely, 2^21116172372 is an apocalyptic number.

It is an amenable number.

21116172372 is an abundant number, since it is smaller than the sum of its proper divisors (28154896524).

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

21116172372 is a wasteful number, since it uses less digits than its factorization.

21116172372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1759681038 (or 1759681036 counting only the distinct ones).

The product of its digits is 7056, while the sum is 33.

The spelling of 21116172372 in words is "twenty-one billion, one hundred sixteen million, one hundred seventy-two thousand, three hundred seventy-two".