66715917 has 4 divisors (see below), whose sum is σ = 88954560. Its totient is φ = 44477276.

The previous prime is 66715907. The next prime is 66715951. The reversal of 66715917 is 71951766.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66715917 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66715907) 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, 11119317 + ... + 11119322.

It is an arithmetic number, because the mean of its divisors is an integer number (22238640).

Almost surely, 2^66715917 is an apocalyptic number.

It is an amenable number.

66715917 is a deficient number, since it is larger than the sum of its proper divisors (22238643).

66715917 is a wasteful number, since it uses less digits than its factorization.

66715917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22238642.

The product of its digits is 79380, while the sum is 42.

The square root of 66715917 is about 8167.9812071282. The cubic root of 66715917 is about 405.5799586186.

The spelling of 66715917 in words is "sixty-six million, seven hundred fifteen thousand, nine hundred seventeen".