31213664 has 12 divisors (see below), whose sum is σ = 61451964. Its totient is φ = 15606816.

The previous prime is 31213643. The next prime is 31213667. The reversal of 31213664 is 46631213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 487682 + ... + 487745.

It is an arithmetic number, because the mean of its divisors is an integer number (5120997).

Almost surely, 2^31213664 is an apocalyptic number.

It is an amenable number.

31213664 is a deficient number, since it is larger than the sum of its proper divisors (30238300).

31213664 is an equidigital number, since it uses as much as digits as its factorization.

31213664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 975437 (or 975429 counting only the distinct ones).

The product of its digits is 2592, while the sum is 26.

The square root of 31213664 is about 5586.9190078253. The cubic root of 31213664 is about 314.8581338163.

Adding to 31213664 its reverse (46631213), we get a palindrome (77844877).

The spelling of 31213664 in words is "thirty-one million, two hundred thirteen thousand, six hundred sixty-four".