65815920 has 60 divisors (see below), whose sum is σ = 221034216. Its totient is φ = 17550720.

The previous prime is 65815907. The next prime is 65815921. The reversal of 65815920 is 2951856.

It is a happy number.

65815920 is a `hidden beast` number, since 6 + 581 + 59 + 20 = 666.

65815920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65815921) 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 11 ways as a sum of consecutive naturals, for example, 44986 + ... + 46425.

Almost surely, 2^65815920 is an apocalyptic number.

65815920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

65815920 is an abundant number, since it is smaller than the sum of its proper divisors (155218296).

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

65815920 is a wasteful number, since it uses less digits than its factorization.

65815920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91430 (or 91421 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The square root of 65815920 is about 8112.7011531302. The cubic root of 65815920 is about 403.7479393608.

The spelling of 65815920 in words is "sixty-five million, eight hundred fifteen thousand, nine hundred twenty".