31680390 has 64 divisors (see below), whose sum is σ = 87381504. Its totient is φ = 7200768.

The previous prime is 31680349. The next prime is 31680403. The reversal of 31680390 is 9308613.

It is a super-2 number, since 2×31680390² = 2007294221104200, which contains 22 as substring.

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

It is a congruent number.

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, 53677 + ... + 54263.

It is an arithmetic number, because the mean of its divisors is an integer number (1365336).

Almost surely, 2^31680390 is an apocalyptic number.

31680390 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 31680390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43690752).

31680390 is an abundant number, since it is smaller than the sum of its proper divisors (55701114).

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

31680390 is a wasteful number, since it uses less digits than its factorization.

31680390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 861.

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 31680390 is about 5628.5335567979. The cubic root of 31680390 is about 316.4196941674.

The spelling of 31680390 in words is "thirty-one million, six hundred eighty thousand, three hundred ninety".