66765915 has 24 divisors (see below), whose sum is σ = 117363168. Its totient is φ = 35105280.

The previous prime is 66765913. The next prime is 66765983. The reversal of 66765915 is 51956766.

It is not a de Polignac number, because 66765915 - 2¹ = 66765913 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (66765911) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7254 + ... + 13643.

It is an arithmetic number, because the mean of its divisors is an integer number (4890132).

Almost surely, 2^66765915 is an apocalyptic number.

66765915 is a deficient number, since it is larger than the sum of its proper divisors (50597253).

66765915 is a wasteful number, since it uses less digits than its factorization.

66765915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20979 (or 20976 counting only the distinct ones).

The product of its digits is 340200, while the sum is 45.

The square root of 66765915 is about 8171.0412433178. The cubic root of 66765915 is about 405.6812494059.

The spelling of 66765915 in words is "sixty-six million, seven hundred sixty-five thousand, nine hundred fifteen".