31720680 has 128 divisors (see below), whose sum is σ = 110419200. Its totient is φ = 8084736.

The previous prime is 31720673. The next prime is 31720699. The reversal of 31720680 is 8602713.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24202 + ... + 25478.

It is an arithmetic number, because the mean of its divisors is an integer number (862650).

Almost surely, 2^31720680 is an apocalyptic number.

31720680 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 31720680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55209600).

31720680 is an abundant number, since it is smaller than the sum of its proper divisors (78698520).

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

31720680 is a wasteful number, since it uses less digits than its factorization.

31720680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1320 (or 1310 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 31720680 is about 5632.1115045780. Note that the first 3 decimals coincide. The cubic root of 31720680 is about 316.5537744707.

It can be divided in two parts, 31720 and 680, that added together give a square (32400 = 180²).

The spelling of 31720680 in words is "thirty-one million, seven hundred twenty thousand, six hundred eighty".