66814792581 has 4 divisors (see below), whose sum is σ = 89086390112. Its totient is φ = 44543195052.

The previous prime is 66814792573. The next prime is 66814792661. The reversal of 66814792581 is 18529741866.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 66814792581 - 2³ = 66814792573 is a prime.

It is a super-2 number, since 2×66814792581² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66814792381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11135798761 + ... + 11135798766.

It is an arithmetic number, because the mean of its divisors is an integer number (22271597528).

Almost surely, 2^66814792581 is an apocalyptic number.

It is an amenable number.

66814792581 is a deficient number, since it is larger than the sum of its proper divisors (22271597531).

66814792581 is a wasteful number, since it uses less digits than its factorization.

66814792581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22271597530.

The product of its digits is 5806080, while the sum is 57.

The spelling of 66814792581 in words is "sixty-six billion, eight hundred fourteen million, seven hundred ninety-two thousand, five hundred eighty-one".