31389939 has 72 divisors (see below), whose sum is σ = 57620160. Its totient is φ = 16353792.

The previous prime is 31389923. The next prime is 31389961. The reversal of 31389939 is 93998313.

It is not a de Polignac number, because 31389939 - 2⁴ = 31389923 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31389894 and 31389903.

It is not an unprimeable number, because it can be changed into a prime (31389989) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 397302 + ... + 397380.

It is an arithmetic number, because the mean of its divisors is an integer number (800280).

Almost surely, 2^31389939 is an apocalyptic number.

31389939 is a deficient number, since it is larger than the sum of its proper divisors (26230221).

31389939 is a wasteful number, since it uses less digits than its factorization.

31389939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169 (or 159 counting only the distinct ones).

The product of its digits is 157464, while the sum is 45.

The square root of 31389939 is about 5602.6724873046. The cubic root of 31389939 is about 315.4497279846.

The spelling of 31389939 in words is "thirty-one million, three hundred eighty-nine thousand, nine hundred thirty-nine".