165661655619 has 32 divisors (see below), whose sum is σ = 226869350400. Its totient is φ = 107476175232.

The previous prime is 165661655611. The next prime is 165661655623. The reversal of 165661655619 is 916556166561.

It is not a de Polignac number, because 165661655619 - 2³ = 165661655611 is a prime.

It is a super-2 number, since 2×165661655619² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (165661655611) 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, 18055117 + ... + 18064289.

It is an arithmetic number, because the mean of its divisors is an integer number (7089667200).

Almost surely, 2^165661655619 is an apocalyptic number.

165661655619 is a deficient number, since it is larger than the sum of its proper divisors (61207694781).

165661655619 is a wasteful number, since it uses less digits than its factorization.

165661655619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9939.

The product of its digits is 8748000, while the sum is 57.

The spelling of 165661655619 in words is "one hundred sixty-five billion, six hundred sixty-one million, six hundred fifty-five thousand, six hundred nineteen".