21756871272 has 32 divisors (see below), whose sum is σ = 57254925600. Its totient is φ = 6870590784.

The previous prime is 21756871271. The next prime is 21756871307. The reversal of 21756871272 is 27217865712.

It is a super-2 number, since 2×21756871272² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21756871271) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23855763 + ... + 23856674.

It is an arithmetic number, because the mean of its divisors is an integer number (1789216425).

Almost surely, 2^21756871272 is an apocalyptic number.

It is an amenable number.

21756871272 is an abundant number, since it is smaller than the sum of its proper divisors (35498054328).

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

21756871272 is a wasteful number, since it uses less digits than its factorization.

21756871272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47712465 (or 47712461 counting only the distinct ones).

The product of its digits is 658560, while the sum is 48.

The spelling of 21756871272 in words is "twenty-one billion, seven hundred fifty-six million, eight hundred seventy-one thousand, two hundred seventy-two".