66979871 has 8 divisors (see below), whose sum is σ = 79017984. Its totient is φ = 55559160.

The previous prime is 66979823. The next prime is 66979873. The reversal of 66979871 is 17897966.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66979871 - 2¹⁸ = 66717727 is a prime.

It is a Duffinian number.

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 polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 154115 + ... + 154548.

It is an arithmetic number, because the mean of its divisors is an integer number (9877248).

Almost surely, 2^66979871 is an apocalyptic number.

66979871 is a deficient number, since it is larger than the sum of its proper divisors (12038113).

66979871 is a wasteful number, since it uses less digits than its factorization.

66979871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 308701.

The product of its digits is 1143072, while the sum is 53.

The square root of 66979871 is about 8184.1231051347. The cubic root of 66979871 is about 406.1141318902.

The spelling of 66979871 in words is "sixty-six million, nine hundred seventy-nine thousand, eight hundred seventy-one".