31665120 has 96 divisors (see below), whose sum is σ = 102241440. Its totient is φ = 8232960.

The previous prime is 31665107. The next prime is 31665121. The reversal of 31665120 is 2156613.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×31665120² = 2005359649228800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31665121) 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 15 ways as a sum of consecutive naturals, for example, 18876 + ... + 20484.

It is an arithmetic number, because the mean of its divisors is an integer number (1065015).

Almost surely, 2^31665120 is an apocalyptic number.

31665120 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 31665120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51120720).

31665120 is an abundant number, since it is smaller than the sum of its proper divisors (70576320).

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

31665120 is a wasteful number, since it uses less digits than its factorization.

31665120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1668 (or 1660 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 31665120 is about 5627.1769120937. The cubic root of 31665120 is about 316.3688477264.

The spelling of 31665120 in words is "thirty-one million, six hundred sixty-five thousand, one hundred twenty".