31923840 has 128 divisors (see below), whose sum is σ = 109670400. Its totient is φ = 7852032.

The previous prime is 31923823. The next prime is 31923847. The reversal of 31923840 is 4832913.

It is a tau number, because it is divible by the number of its divisors (128).

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 = 31923798 and 31923807.

It is not an unprimeable number, because it can be changed into a prime (31923847) 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, 24321 + ... + 25599.

It is an arithmetic number, because the mean of its divisors is an integer number (856800).

Almost surely, 2^31923840 is an apocalyptic number.

31923840 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 31923840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (54835200).

31923840 is an abundant number, since it is smaller than the sum of its proper divisors (77746560).

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

31923840 is a wasteful number, since it uses less digits than its factorization.

31923840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1314 (or 1302 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 31923840 is about 5650.1185828264. The cubic root of 31923840 is about 317.2281426805.

The spelling of 31923840 in words is "thirty-one million, nine hundred twenty-three thousand, eight hundred forty".