31813830 has 128 divisors (see below), whose sum is σ = 91238400. Its totient is φ = 7869312.

The previous prime is 31813819. The next prime is 31813861. The reversal of 31813830 is 3831813.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 31813794 and 31813803.

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 291816 + ... + 291924.

It is an arithmetic number, because the mean of its divisors is an integer number (712800).

Almost surely, 2^31813830 is an apocalyptic number.

31813830 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 31813830, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45619200).

31813830 is an abundant number, since it is smaller than the sum of its proper divisors (59424570).

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

31813830 is a wasteful number, since it uses less digits than its factorization.

31813830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 31813830 is about 5640.3749875341. The cubic root of 31813830 is about 316.8633324369.

The spelling of 31813830 in words is "thirty-one million, eight hundred thirteen thousand, eight hundred thirty".