19645354206864 has 135 divisors (see below), whose sum is σ = 58406736360297. Its totient is φ = 6162964710912.

The previous prime is 19645354206787. The next prime is 19645354206889. The reversal of 19645354206864 is 46860245354691.

It is a happy number.

The square root of 19645354206864 is 4432308.

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

19645354206864 is a `hidden beast` number, since 1 + 9 + 6 + 4 + 5 + 3 + 542 + 0 + 6 + 86 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 15294825939600 + 4350528267264 = 3910860^2 + 2085792^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 904179969 + ... + 904201695.

Almost surely, 2^{19645354206864} is an apocalyptic number.

19645354206864 is the 4432308-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19645354206864

19645354206864 is an abundant number, since it is smaller than the sum of its proper divisors (38761382153433).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19645354206864 is an frugal number, since it uses more digits than its factorization.

19645354206864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43502 (or 21749 counting only the distinct ones).

The product of its (nonzero) digits is 149299200, while the sum is 63.

The spelling of 19645354206864 in words is "nineteen trillion, six hundred forty-five billion, three hundred fifty-four million, two hundred six thousand, eight hundred sixty-four".