66720924 has 36 divisors (see below), whose sum is σ = 169233064. Its totient is φ = 22164192.

The previous prime is 66720923. The next prime is 66720947. The reversal of 66720924 is 42902766.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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 (66720923) 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, 8034 + ... + 14070.

Almost surely, 2^66720924 is an apocalyptic number.

It is an amenable number.

66720924 is an abundant number, since it is smaller than the sum of its proper divisors (102512140).

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

66720924 is a wasteful number, since it uses less digits than its factorization.

66720924 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6354 (or 6349 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The square root of 66720924 is about 8168.2877030624. The cubic root of 66720924 is about 405.5901045635.

The spelling of 66720924 in words is "sixty-six million, seven hundred twenty thousand, nine hundred twenty-four".