31993128 has 24 divisors (see below), whose sum is σ = 86648250. Its totient is φ = 10664352.

The previous prime is 31993127. The next prime is 31993187. The reversal of 31993128 is 82139913.

It can be written as a sum of positive squares in only one way, i.e., 29615364 + 2377764 = 5442^2 + 1542^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 31993092 and 31993101.

It is not an unprimeable number, because it can be changed into a prime (31993121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 222103 + ... + 222246.

Almost surely, 2^31993128 is an apocalyptic number.

It is an amenable number.

31993128 is an abundant number, since it is smaller than the sum of its proper divisors (54655122).

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

31993128 is a wasteful number, since it uses less digits than its factorization.

31993128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 444361 (or 444354 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 31993128 is about 5656.2468121538. The cubic root of 31993128 is about 317.4574824749.

The spelling of 31993128 in words is "thirty-one million, nine hundred ninety-three thousand, one hundred twenty-eight".