31864440 has 64 divisors (see below), whose sum is σ = 96370560. Its totient is φ = 8428160.

The previous prime is 31864439. The next prime is 31864457. The reversal of 31864440 is 4446813.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 31864398 and 31864407.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14707 + ... + 16733.

It is an arithmetic number, because the mean of its divisors is an integer number (1505790).

Almost surely, 2^31864440 is an apocalyptic number.

31864440 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31864440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48185280).

31864440 is an abundant number, since it is smaller than the sum of its proper divisors (64506120).

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

31864440 is a wasteful number, since it uses less digits than its factorization.

31864440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2172 (or 2168 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 31864440 is about 5644.8596085288. The cubic root of 31864440 is about 317.0312673368.

It can be divided in two parts, 3186 and 4440, that added together give a triangular number (7626 = T₁₂₃).

The spelling of 31864440 in words is "thirty-one million, eight hundred sixty-four thousand, four hundred forty".