31531361013 has 6 divisors (see below), whose sum is σ = 45545299254. Its totient is φ = 21020907336.

The previous prime is 31531360981. The next prime is 31531361033. The reversal of 31531361013 is 31016313513.

31531361013 is a `hidden beast` number, since 3 + 1 + 5 + 31 + 3 + 610 + 13 = 666.

It can be written as a sum of positive squares in only one way, i.e., 25108620849 + 6422740164 = 158457^2 + 80142^2 .

It is not a de Polignac number, because 31531361013 - 2⁵ = 31531360981 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31531361033) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1751742270 + ... + 1751742287.

It is an arithmetic number, because the mean of its divisors is an integer number (7590883209).

Almost surely, 2^31531361013 is an apocalyptic number.

It is an amenable number.

31531361013 is a deficient number, since it is larger than the sum of its proper divisors (14013938241).

31531361013 is a wasteful number, since it uses less digits than its factorization.

31531361013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3503484563 (or 3503484560 counting only the distinct ones).

The product of its (nonzero) digits is 2430, while the sum is 27.

Adding to 31531361013 its reverse (31016313513), we get a palindrome (62547674526).

The spelling of 31531361013 in words is "thirty-one billion, five hundred thirty-one million, three hundred sixty-one thousand, thirteen".