66365661 has 4 divisors (see below), whose sum is σ = 88487552. Its totient is φ = 44243772.

The previous prime is 66365653. The next prime is 66365669. The reversal of 66365661 is 16656366.

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 an interprime number because it is at equal distance from previous prime (66365653) and next prime (66365669).

It is not a de Polignac number, because 66365661 - 2³ = 66365653 is a prime.

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 (66365669) 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, 11060941 + ... + 11060946.

It is an arithmetic number, because the mean of its divisors is an integer number (22121888).

Almost surely, 2^66365661 is an apocalyptic number.

It is an amenable number.

66365661 is a deficient number, since it is larger than the sum of its proper divisors (22121891).

66365661 is a wasteful number, since it uses less digits than its factorization.

66365661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22121890.

The product of its digits is 116640, while the sum is 39.

The square root of 66365661 is about 8146.5121984810. The cubic root of 66365661 is about 404.8689531814.

The spelling of 66365661 in words is "sixty-six million, three hundred sixty-five thousand, six hundred sixty-one".