31138216 has 16 divisors (see below), whose sum is σ = 58744800. Its totient is φ = 15472944.

The previous prime is 31138213. The next prime is 31138249. The reversal of 31138216 is 61283113.

It is not an unprimeable number, because it can be changed into a prime (31138213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10636 + ... + 13243.

It is an arithmetic number, because the mean of its divisors is an integer number (3671550).

Almost surely, 2^31138216 is an apocalyptic number.

It is an amenable number.

31138216 is a deficient number, since it is larger than the sum of its proper divisors (27606584).

31138216 is a wasteful number, since it uses less digits than its factorization.

31138216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24048 (or 24044 counting only the distinct ones).

The product of its digits is 864, while the sum is 25.

The square root of 31138216 is about 5580.1627216417. The cubic root of 31138216 is about 314.6042430595.

The spelling of 31138216 in words is "thirty-one million, one hundred thirty-eight thousand, two hundred sixteen".