66621764 has 12 divisors (see below), whose sum is σ = 127187088. Its totient is φ = 30282600.

The previous prime is 66621713. The next prime is 66621767. The reversal of 66621764 is 46712666.

It is not an unprimeable number, because it can be changed into a prime (66621767) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 757022 + ... + 757109.

It is an arithmetic number, because the mean of its divisors is an integer number (10598924).

Almost surely, 2^66621764 is an apocalyptic number.

It is an amenable number.

66621764 is a deficient number, since it is larger than the sum of its proper divisors (60565324).

66621764 is a wasteful number, since it uses less digits than its factorization.

66621764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1514146 (or 1514144 counting only the distinct ones).

The product of its digits is 72576, while the sum is 38.

The square root of 66621764 is about 8162.2156305748. The cubic root of 66621764 is about 405.3890768956.

The spelling of 66621764 in words is "sixty-six million, six hundred twenty-one thousand, seven hundred sixty-four".