18956171645 has 18 divisors (see below), whose sum is σ = 23117141502. Its totient is φ = 14922339696.

The previous prime is 18956171627. The next prime is 18956171653. The reversal of 18956171645 is 54617165981.

It can be written as a sum of positive squares in only one way, i.e., 15164937316 + 3791234329 = 123146^2 + 61573^2 .

It is not a de Polignac number, because 18956171645 - 2¹⁴ = 18956155261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 20626496 + ... + 20627414.

It is an arithmetic number, because the mean of its divisors is an integer number (1284285639).

Almost surely, 2^18956171645 is an apocalyptic number.

It is an amenable number.

18956171645 is a deficient number, since it is larger than the sum of its proper divisors (4160969857).

18956171645 is an frugal number, since it uses more digits than its factorization.

18956171645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1977 (or 991 counting only the distinct ones).

The product of its digits is 1814400, while the sum is 53.

The spelling of 18956171645 in words is "eighteen billion, nine hundred fifty-six million, one hundred seventy-one thousand, six hundred forty-five".