66573979919 has 16 divisors (see below), whose sum is σ = 68848704000. Its totient is φ = 64342652640.

The previous prime is 66573979907. The next prime is 66573979921. The reversal of 66573979919 is 91997937566.

It is a cyclic number.

It is not a de Polignac number, because 66573979919 - 2²⁰ = 66572931343 is a prime.

It is a super-5 number, since 5×66573979919⁵ (a number of 55 digits) contains 55555 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (71).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66573979019) 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, 1481717 + ... + 1525985.

It is an arithmetic number, because the mean of its divisors is an integer number (4303044000).

Almost surely, 2^66573979919 is an apocalyptic number.

66573979919 is a deficient number, since it is larger than the sum of its proper divisors (2274724081).

66573979919 is a wasteful number, since it uses less digits than its factorization.

66573979919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44758.

The product of its digits is 173604060, while the sum is 71.

The spelling of 66573979919 in words is "sixty-six billion, five hundred seventy-three million, nine hundred seventy-nine thousand, nine hundred nineteen".