71721071631 has 12 divisors (see below), whose sum is σ = 113015022120. Its totient is φ = 43467316080.

The previous prime is 71721071599. The next prime is 71721071659. The reversal of 71721071631 is 13617012717.

71721071631 is a `hidden beast` number, since 7 + 1 + 7 + 2 + 10 + 7 + 1 + 631 = 666.

It is not a de Polignac number, because 71721071631 - 2⁵ = 71721071599 is a prime.

It is a super-2 number, since 2×71721071631² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71721061631) 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 11 ways as a sum of consecutive naturals, for example, 362227536 + ... + 362227733.

It is an arithmetic number, because the mean of its divisors is an integer number (9417918510).

Almost surely, 2^71721071631 is an apocalyptic number.

71721071631 is a deficient number, since it is larger than the sum of its proper divisors (41293950489).

71721071631 is a wasteful number, since it uses less digits than its factorization.

71721071631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 724455286 (or 724455283 counting only the distinct ones).

The product of its (nonzero) digits is 12348, while the sum is 36.

The spelling of 71721071631 in words is "seventy-one billion, seven hundred twenty-one million, seventy-one thousand, six hundred thirty-one".