31031009138 has 4 divisors (see below), whose sum is σ = 46546513710. Its totient is φ = 15515504568.

The previous prime is 31031009137. The next prime is 31031009189. The reversal of 31031009138 is 83190013013.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 29671096009 + 1359913129 = 172253^2 + 36877^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 31031009138.

It is not an unprimeable number, because it can be changed into a prime (31031009137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7757752283 + ... + 7757752286.

Almost surely, 2^31031009138 is an apocalyptic number.

31031009138 is a deficient number, since it is larger than the sum of its proper divisors (15515504572).

31031009138 is a wasteful number, since it uses less digits than its factorization.

31031009138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15515504571.

The product of its (nonzero) digits is 1944, while the sum is 29.

The spelling of 31031009138 in words is "thirty-one billion, thirty-one million, nine thousand, one hundred thirty-eight".