19921998025 has 6 divisors (see below), whose sum is σ = 24703277582. Its totient is φ = 15937598400.

The previous prime is 19921998017. The next prime is 19921998043. The reversal of 19921998025 is 52089912991.

It can be written as a sum of positive squares in 3 ways, for example, as 3637175481 + 16284822544 = 60309^2 + 127612^2 .

It is not a de Polignac number, because 19921998025 - 2³ = 19921998017 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 398439936 + ... + 398439985.

Almost surely, 2^19921998025 is an apocalyptic number.

It is an amenable number.

19921998025 is a deficient number, since it is larger than the sum of its proper divisors (4781279557).

19921998025 is an equidigital number, since it uses as much as digits as its factorization.

19921998025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 796879931 (or 796879926 counting only the distinct ones).

The product of its (nonzero) digits is 1049760, while the sum is 55.

The spelling of 19921998025 in words is "nineteen billion, nine hundred twenty-one million, nine hundred ninety-eight thousand, twenty-five".