19666197577 has 6 divisors (see below), whose sum is σ = 21295350222. Its totient is φ = 18153412992.

The previous prime is 19666197563. The next prime is 19666197583. The reversal of 19666197577 is 77579166691.

It can be written as a sum of positive squares in 3 ways, for example, as 2352638016 + 17313559561 = 48504^2 + 131581^2 .

It is not a de Polignac number, because 19666197577 - 2¹⁵ = 19666164809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19666197517) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 58183848 + ... + 58184185.

It is an arithmetic number, because the mean of its divisors is an integer number (3549225037).

Almost surely, 2^19666197577 is an apocalyptic number.

It is an amenable number.

19666197577 is a deficient number, since it is larger than the sum of its proper divisors (1629152645).

19666197577 is a wasteful number, since it uses less digits than its factorization.

19666197577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116368059 (or 116368046 counting only the distinct ones).

The product of its digits is 30005640, while the sum is 64.

The spelling of 19666197577 in words is "nineteen billion, six hundred sixty-six million, one hundred ninety-seven thousand, five hundred seventy-seven".