165666501651 has 32 divisors (see below), whose sum is σ = 256279592448. Its totient is φ = 93229044480.

The previous prime is 165666501643. The next prime is 165666501691. The reversal of 165666501651 is 156105666561.

It is not a de Polignac number, because 165666501651 - 2³ = 165666501643 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165666501651.

It is not an unprimeable number, because it can be changed into a prime (165666501691) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6207031 + ... + 6233663.

It is an arithmetic number, because the mean of its divisors is an integer number (8008737264).

Almost surely, 2^165666501651 is an apocalyptic number.

165666501651 is a deficient number, since it is larger than the sum of its proper divisors (90613090797).

165666501651 is a wasteful number, since it uses less digits than its factorization.

165666501651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31131.

The product of its (nonzero) digits is 972000, while the sum is 48.

The spelling of 165666501651 in words is "one hundred sixty-five billion, six hundred sixty-six million, five hundred one thousand, six hundred fifty-one".