21756136431 has 8 divisors (see below), whose sum is σ = 29008967680. Its totient is φ = 14503698072.

The previous prime is 21756136417. The next prime is 21756136433. The reversal of 21756136431 is 13463165712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21756136431 - 2²⁵ = 21722581999 is a prime.

It is a super-2 number, since 2×21756136431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21756136431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21756136433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74256 + ... + 221418.

It is an arithmetic number, because the mean of its divisors is an integer number (3626120960).

Almost surely, 2^21756136431 is an apocalyptic number.

21756136431 is a deficient number, since it is larger than the sum of its proper divisors (7252831249).

21756136431 is a wasteful number, since it uses less digits than its factorization.

21756136431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196445.

The product of its digits is 90720, while the sum is 39.

The spelling of 21756136431 in words is "twenty-one billion, seven hundred fifty-six million, one hundred thirty-six thousand, four hundred thirty-one".