31218197 has 6 divisors (see below), whose sum is σ = 32948118. Its totient is φ = 29574792.

The previous prime is 31218163. The next prime is 31218211. The reversal of 31218197 is 79181213.

It can be written as a sum of positive squares in only one way, i.e., 17631601 + 13586596 = 4199^2 + 3686^2 .

It is not a de Polignac number, because 31218197 - 2⁶ = 31218133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31218157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 42878 + ... + 43599.

It is an arithmetic number, because the mean of its divisors is an integer number (5491353).

Almost surely, 2^31218197 is an apocalyptic number.

It is an amenable number.

31218197 is a deficient number, since it is larger than the sum of its proper divisors (1729921).

31218197 is an equidigital number, since it uses as much as digits as its factorization.

31218197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86515 (or 86496 counting only the distinct ones).

The product of its digits is 3024, while the sum is 32.

The square root of 31218197 is about 5587.3246728645. The cubic root of 31218197 is about 314.8733748214.

The spelling of 31218197 in words is "thirty-one million, two hundred eighteen thousand, one hundred ninety-seven".