31121040 has 40 divisors (see below), whose sum is σ = 96475968. Its totient is φ = 8298880.

The previous prime is 31121039. The next prime is 31121059. The reversal of 31121040 is 4012113.

Added to its reverse (4012113) it gives a triangular number (35133153 = T₈₃₈₂).

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 64596 + ... + 65075.

Almost surely, 2^31121040 is an apocalyptic number.

31121040 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31121040 is an abundant number, since it is smaller than the sum of its proper divisors (65354928).

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

31121040 is a wasteful number, since it uses less digits than its factorization.

31121040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129687 (or 129681 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 31121040 is about 5578.6234861299. The cubic root of 31121040 is about 314.5463866477.

Adding to 31121040 its reverse (4012113), we get a palindrome (35133153).

The spelling of 31121040 in words is "thirty-one million, one hundred twenty-one thousand, forty".