66979872 has 60 divisors (see below), whose sum is σ = 196993566. Its totient is φ = 22325760.

The previous prime is 66979823. The next prime is 66979873. The reversal of 66979872 is 27897966.

It can be written as a sum of positive squares in only one way, i.e., 62157456 + 4822416 = 7884^2 + 2196^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66979873) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 10329 + ... + 15512.

Almost surely, 2^66979872 is an apocalyptic number.

It is an amenable number.

66979872 is an abundant number, since it is smaller than the sum of its proper divisors (130013694).

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

66979872 is a wasteful number, since it uses less digits than its factorization.

66979872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25863 (or 25846 counting only the distinct ones).

The product of its digits is 2286144, while the sum is 54.

The square root of 66979872 is about 8184.1231662286. The cubic root of 66979872 is about 406.1141339112.

The spelling of 66979872 in words is "sixty-six million, nine hundred seventy-nine thousand, eight hundred seventy-two".