31213745 has 16 divisors (see below), whose sum is σ = 38857728. Its totient is φ = 24045120.

The previous prime is 31213739. The next prime is 31213753. The reversal of 31213745 is 54731213.

It is not a de Polignac number, because 31213745 - 2⁴ = 31213729 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42572 + ... + 43298.

It is an arithmetic number, because the mean of its divisors is an integer number (2428608).

Almost surely, 2^31213745 is an apocalyptic number.

It is an amenable number.

31213745 is a deficient number, since it is larger than the sum of its proper divisors (7643983).

31213745 is a wasteful number, since it uses less digits than its factorization.

31213745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1040.

The product of its digits is 2520, while the sum is 26.

The square root of 31213745 is about 5586.9262568965. The cubic root of 31213745 is about 314.8584061702.

Adding to 31213745 its reverse (54731213), we get a palindrome (85944958).

The spelling of 31213745 in words is "thirty-one million, two hundred thirteen thousand, seven hundred forty-five".