31523281645 has 32 divisors (see below), whose sum is σ = 41560108128. Its totient is φ = 22855385088.

The previous prime is 31523281613. The next prime is 31523281723. The reversal of 31523281645 is 54618232513.

It can be written as a sum of positive squares in 16 ways, for example, as 546577641 + 30976704004 = 23379^2 + 176002^2 .

It is a cyclic number.

It is not a de Polignac number, because 31523281645 - 2⁵ = 31523281613 is a prime.

It is a super-3 number, since 3×31523281645³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31523281598 and 31523281607.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 253399 + ... + 356731.

It is an arithmetic number, because the mean of its divisors is an integer number (1298753379).

Almost surely, 2^31523281645 is an apocalyptic number.

It is an amenable number.

31523281645 is a deficient number, since it is larger than the sum of its proper divisors (10036826483).

31523281645 is a wasteful number, since it uses less digits than its factorization.

31523281645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103489.

The product of its digits is 172800, while the sum is 40.

The spelling of 31523281645 in words is "thirty-one billion, five hundred twenty-three million, two hundred eighty-one thousand, six hundred forty-five".