19790655871561 has 27 divisors (see below), whose sum is σ = 20271901606047. Its totient is φ = 19320747413760.

The previous prime is 19790655871559. The next prime is 19790655871633. The reversal of 19790655871561 is 16517855609791.

The square root of 19790655871561 is 4448669.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 13 ways, for example, as 8776886181561 + 11013769690000 = 2962581^2 + 3318700^2 .

It is not a de Polignac number, because 19790655871561 - 2¹ = 19790655871559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19790655871061) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 63228932341 + ... + 63228932653.

Almost surely, 2^{19790655871561} is an apocalyptic number.

19790655871561 is the 4448669-th square number.

19790655871561 is the 2224335-th centered octagonal number.

It is an amenable number.

19790655871561 is a deficient number, since it is larger than the sum of its proper divisors (481245734486).

19790655871561 is an frugal number, since it uses more digits than its factorization.

19790655871561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1214 (or 607 counting only the distinct ones).

The product of its (nonzero) digits is 142884000, while the sum is 70.

The spelling of 19790655871561 in words is "nineteen trillion, seven hundred ninety billion, six hundred fifty-five million, eight hundred seventy-one thousand, five hundred sixty-one".