81457475631 has 32 divisors (see below), whose sum is σ = 125080347648. Its totient is φ = 46189785600.

The previous prime is 81457475629. The next prime is 81457475651. The reversal of 81457475631 is 13657475418.

It is a happy number.

It is not a de Polignac number, because 81457475631 - 2¹ = 81457475629 is a prime.

It is a super-3 number, since 3×81457475631³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81457475651) 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, 3084921 + ... + 3111213.

It is an arithmetic number, because the mean of its divisors is an integer number (3908760864).

Almost surely, 2^81457475631 is an apocalyptic number.

81457475631 is a deficient number, since it is larger than the sum of its proper divisors (43622872017).

81457475631 is a wasteful number, since it uses less digits than its factorization.

81457475631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27431.

The product of its digits is 2822400, while the sum is 51.

The spelling of 81457475631 in words is "eighty-one billion, four hundred fifty-seven million, four hundred seventy-five thousand, six hundred thirty-one".