19825572661 has 2 divisors, whose sum is σ = 19825572662. Its totient is φ = 19825572660.

The previous prime is 19825572649. The next prime is 19825572707. The reversal of 19825572661 is 16627552891.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15417940561 + 4407632100 = 124169^2 + 66390^2 .

It is a cyclic number.

It is not a de Polignac number, because 19825572661 - 2²⁵ = 19792018229 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19825572599 and 19825572608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19825572961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9912786330 + 9912786331.

It is an arithmetic number, because the mean of its divisors is an integer number (9912786331).

Almost surely, 2^19825572661 is an apocalyptic number.

It is an amenable number.

19825572661 is a deficient number, since it is larger than the sum of its proper divisors (1).

19825572661 is an equidigital number, since it uses as much as digits as its factorization.

19825572661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1814400, while the sum is 52.

The spelling of 19825572661 in words is "nineteen billion, eight hundred twenty-five million, five hundred seventy-two thousand, six hundred sixty-one".