16556540425 has 6 divisors (see below), whose sum is σ = 20530110158. Its totient is φ = 13245232320.

The previous prime is 16556540323. The next prime is 16556540437. The reversal of 16556540425 is 52404565561.

It can be written as a sum of positive squares in 3 ways, for example, as 1689127801 + 14867412624 = 41099^2 + 121932^2 .

It is a de Polignac number, because none of the positive numbers 2^k-16556540425 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, 331130784 + ... + 331130833.

Almost surely, 2^16556540425 is an apocalyptic number.

It is an amenable number.

16556540425 is a deficient number, since it is larger than the sum of its proper divisors (3973569733).

16556540425 is an equidigital number, since it uses as much as digits as its factorization.

16556540425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662261627 (or 662261622 counting only the distinct ones).

The product of its (nonzero) digits is 720000, while the sum is 43.

The spelling of 16556540425 in words is "sixteen billion, five hundred fifty-six million, five hundred forty thousand, four hundred twenty-five".