66715807 has 4 divisors (see below), whose sum is σ = 66943800. Its totient is φ = 66487816.

The previous prime is 66715799. The next prime is 66715841. The reversal of 66715807 is 70851766.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66715807 - 2³ = 66715799 is a prime.

It is a super-2 number, since 2×66715807² = 8901997807322498, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66715807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66715867) 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, 113557 + ... + 114142.

It is an arithmetic number, because the mean of its divisors is an integer number (16735950).

Almost surely, 2^66715807 is an apocalyptic number.

66715807 is a deficient number, since it is larger than the sum of its proper divisors (227993).

66715807 is a wasteful number, since it uses less digits than its factorization.

66715807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227992.

The product of its (nonzero) digits is 70560, while the sum is 40.

The square root of 66715807 is about 8167.9744735155. The cubic root of 66715807 is about 405.5797357142.

The spelling of 66715807 in words is "sixty-six million, seven hundred fifteen thousand, eight hundred seven".