66979539 has 24 divisors (see below), whose sum is σ = 106546752. Its totient is φ = 40207920.

The previous prime is 66979489. The next prime is 66979543. The reversal of 66979539 is 93597966.

It is not a de Polignac number, because 66979539 - 2⁷ = 66979411 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66979039) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7432 + ... + 13754.

It is an arithmetic number, because the mean of its divisors is an integer number (4439448).

Almost surely, 2^66979539 is an apocalyptic number.

66979539 is a deficient number, since it is larger than the sum of its proper divisors (39567213).

66979539 is a wasteful number, since it uses less digits than its factorization.

66979539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6447 (or 6444 counting only the distinct ones).

The product of its digits is 2755620, while the sum is 54.

The square root of 66979539 is about 8184.1028219347. The cubic root of 66979539 is about 406.1134608920.

It can be divided in two parts, 669 and 79539, that added together give a palindrome (80208).

The spelling of 66979539 in words is "sixty-six million, nine hundred seventy-nine thousand, five hundred thirty-nine".