66939879 has 8 divisors (see below), whose sum is σ = 89294320. Its totient is φ = 44606016.

The previous prime is 66939877. The next prime is 66939883. The reversal of 66939879 is 97893966.

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

It is not a de Polignac number, because 66939879 - 2¹ = 66939877 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 (66939877) 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, 5739 + ... + 12915.

It is an arithmetic number, because the mean of its divisors is an integer number (11161790).

Almost surely, 2^66939879 is an apocalyptic number.

66939879 is a deficient number, since it is larger than the sum of its proper divisors (22354441).

66939879 is a wasteful number, since it uses less digits than its factorization.

66939879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10289.

The product of its digits is 4408992, while the sum is 57.

The square root of 66939879 is about 8181.6794730666. The cubic root of 66939879 is about 406.0332889462.

The spelling of 66939879 in words is "sixty-six million, nine hundred thirty-nine thousand, eight hundred seventy-nine".