66619808979 has 16 divisors (see below), whose sum is σ = 90105360000. Its totient is φ = 43774572096.

The previous prime is 66619808977. The next prime is 66619808989. The reversal of 66619808979 is 97980891666.

It is not a de Polignac number, because 66619808979 - 2¹ = 66619808977 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66619808971) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 215272 + ... + 423770.

It is an arithmetic number, because the mean of its divisors is an integer number (5631585000).

Almost surely, 2^66619808979 is an apocalyptic number.

66619808979 is a deficient number, since it is larger than the sum of its proper divisors (23485551021).

66619808979 is a wasteful number, since it uses less digits than its factorization.

66619808979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210034.

The product of its (nonzero) digits is 70543872, while the sum is 69.

The spelling of 66619808979 in words is "sixty-six billion, six hundred nineteen million, eight hundred eight thousand, nine hundred seventy-nine".