31161640 has 32 divisors (see below), whose sum is σ = 71827560. Its totient is φ = 12160000.

The previous prime is 31161607. The next prime is 31161643. The reversal of 31161640 is 4616113.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10929636 + 20232004 = 3306^2 + 4498^2 .

It is not an unprimeable number, because it can be changed into a prime (31161643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7861 + ... + 11140.

Almost surely, 2^31161640 is an apocalyptic number.

It is an amenable number.

31161640 is an abundant number, since it is smaller than the sum of its proper divisors (40665920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31161640 is a wasteful number, since it uses less digits than its factorization.

31161640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19053 (or 19049 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 31161640 is about 5582.2611905929. The cubic root of 31161640 is about 314.6831112332.

Adding to 31161640 its reverse (4616113), we get a palindrome (35777753).

The spelling of 31161640 in words is "thirty-one million, one hundred sixty-one thousand, six hundred forty".