66528720 has 60 divisors (see below), whose sum is σ = 223428036. Its totient is φ = 17740800.

The previous prime is 66528713. The next prime is 66528731. The reversal of 66528720 is 2782566.

66528720 is a `hidden beast` number, since 66 + 528 + 72 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 43718544 + 22810176 = 6612^2 + 4776^2 .

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 an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 45481 + ... + 46920.

Almost surely, 2^66528720 is an apocalyptic number.

66528720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66528720 is an abundant number, since it is smaller than the sum of its proper divisors (156899316).

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

66528720 is a wasteful number, since it uses less digits than its factorization.

66528720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92420 (or 92411 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 66528720 is about 8156.5139612459. The cubic root of 66528720 is about 405.2002667525.

The spelling of 66528720 in words is "sixty-six million, five hundred twenty-eight thousand, seven hundred twenty".