31145921 has 16 divisors (see below), whose sum is σ = 34954560. Its totient is φ = 27578880.

The previous prime is 31145909. The next prime is 31145941. The reversal of 31145921 is 12954113.

It is not a de Polignac number, because 31145921 - 2⁶ = 31145857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31145941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67925 + ... + 68381.

It is an arithmetic number, because the mean of its divisors is an integer number (2184660).

Almost surely, 2^31145921 is an apocalyptic number.

It is an amenable number.

31145921 is a deficient number, since it is larger than the sum of its proper divisors (3808639).

31145921 is a wasteful number, since it uses less digits than its factorization.

31145921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 704.

The product of its digits is 1080, while the sum is 26.

The square root of 31145921 is about 5580.8530709919. The cubic root of 31145921 is about 314.6301900157.

The spelling of 31145921 in words is "thirty-one million, one hundred forty-five thousand, nine hundred twenty-one".