66511720 has 32 divisors (see below), whose sum is σ = 163257120. Its totient is φ = 24185920.

The previous prime is 66511651. The next prime is 66511727. The reversal of 66511720 is 2711566.

It is not an unprimeable number, because it can be changed into a prime (66511727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75142 + ... + 76021.

It is an arithmetic number, because the mean of its divisors is an integer number (5101785).

Almost surely, 2^66511720 is an apocalyptic number.

It is an amenable number.

66511720 is an abundant number, since it is smaller than the sum of its proper divisors (96745400).

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

66511720 is a wasteful number, since it uses less digits than its factorization.

66511720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151185 (or 151181 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 66511720 is about 8155.4717827971. The cubic root of 66511720 is about 405.1657503745.

The spelling of 66511720 in words is "sixty-six million, five hundred eleven thousand, seven hundred twenty".