64818720 has 72 divisors (see below), whose sum is σ = 221198796. Its totient is φ = 17284608.

The previous prime is 64818707. The next prime is 64818727. The reversal of 64818720 is 2781846.

64818720 is a `hidden beast` number, since 648 + 1 + 8 + 7 + 2 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 55890576 + 8928144 = 7476^2 + 2988^2 .

It is a tau number, because it is divible by the number of its divisors (72).

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

It is not an unprimeable number, because it can be changed into a prime (64818727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21067 + ... + 23946.

Almost surely, 2^64818720 is an apocalyptic number.

64818720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

64818720 is an abundant number, since it is smaller than the sum of its proper divisors (156380076).

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

64818720 is a wasteful number, since it uses less digits than its factorization.

64818720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45034 (or 45023 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 64818720 is about 8051.0073903829. The cubic root of 64818720 is about 401.6984446735.

The spelling of 64818720 in words is "sixty-four million, eight hundred eighteen thousand, seven hundred twenty".