31138880 has 112 divisors (see below), whose sum is σ = 79394304. Its totient is φ = 11612160.

The previous prime is 31138879. The next prime is 31138889. The reversal of 31138880 is 8883113.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (31138889) 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, 426524 + ... + 426596.

Almost surely, 2^31138880 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31138880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39697152).

31138880 is an abundant number, since it is smaller than the sum of its proper divisors (48255424).

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

31138880 is a wasteful number, since it uses less digits than its factorization.

31138880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 31138880 is about 5580.2222177974. Note that the first 4 decimals coincide. The cubic root of 31138880 is about 314.6064792798.

The spelling of 31138880 in words is "thirty-one million, one hundred thirty-eight thousand, eight hundred eighty".