66979721365 has 8 divisors (see below), whose sum is σ = 80505516960. Its totient is φ = 53497209552.

The previous prime is 66979721351. The next prime is 66979721399. The reversal of 66979721365 is 56312797966.

66979721365 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 66979721365 - 2¹³ = 66979713173 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10817539 + ... + 10823728.

It is an arithmetic number, because the mean of its divisors is an integer number (10063189620).

Almost surely, 2^66979721365 is an apocalyptic number.

It is an amenable number.

66979721365 is a deficient number, since it is larger than the sum of its proper divisors (13525795595).

66979721365 is a wasteful number, since it uses less digits than its factorization.

66979721365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21641891.

The product of its digits is 25719120, while the sum is 61.

The spelling of 66979721365 in words is "sixty-six billion, nine hundred seventy-nine million, seven hundred twenty-one thousand, three hundred sixty-five".