66979880 has 64 divisors (see below), whose sum is σ = 165473280. Its totient is φ = 24198400.

The previous prime is 66979877. The next prime is 66979897. The reversal of 66979880 is 8897966.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 83642 + ... + 84438.

It is an arithmetic number, because the mean of its divisors is an integer number (2585520).

Almost surely, 2^66979880 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66979880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82736640).

66979880 is an abundant number, since it is smaller than the sum of its proper divisors (98493400).

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

66979880 is a wasteful number, since it uses less digits than its factorization.

66979880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1010 (or 1006 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 53.

The square root of 66979880 is about 8184.1236549798. The cubic root of 66979880 is about 406.1141500798.

The spelling of 66979880 in words is "sixty-six million, nine hundred seventy-nine thousand, eight hundred eighty".