31661680 has 40 divisors (see below), whose sum is σ = 74129184. Its totient is φ = 12576000.

The previous prime is 31661611. The next prime is 31661681. The reversal of 31661680 is 8616613.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31661681) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 10770 + ... + 13390.

Almost surely, 2^31661680 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31661680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37064592).

31661680 is an abundant number, since it is smaller than the sum of its proper divisors (42467504).

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

31661680 is a wasteful number, since it uses less digits than its factorization.

31661680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2785 (or 2779 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 31661680 is about 5626.8712443062. The cubic root of 31661680 is about 316.3573908695.

The spelling of 31661680 in words is "thirty-one million, six hundred sixty-one thousand, six hundred eighty".