31389531 has 16 divisors (see below), whose sum is σ = 44457984. Its totient is φ = 19631744.

The previous prime is 31389509. The next prime is 31389551. The reversal of 31389531 is 13598313.

It is a cyclic number.

It is not a de Polignac number, because 31389531 - 2⁷ = 31389403 is a prime.

It is a super-2 number, since 2×31389531² = 1970605312799922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31389492 and 31389501.

It is not an unprimeable number, because it can be changed into a prime (31389551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18730 + ... + 20336.

It is an arithmetic number, because the mean of its divisors is an integer number (2778624).

Almost surely, 2^31389531 is an apocalyptic number.

31389531 is a deficient number, since it is larger than the sum of its proper divisors (13068453).

31389531 is a wasteful number, since it uses less digits than its factorization.

31389531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2010.

The product of its digits is 9720, while the sum is 33.

The square root of 31389531 is about 5602.6360759914. The cubic root of 31389531 is about 315.4483612617.

The spelling of 31389531 in words is "thirty-one million, three hundred eighty-nine thousand, five hundred thirty-one".