20251904581 has 2 divisors, whose sum is σ = 20251904582. Its totient is φ = 20251904580.

The previous prime is 20251904513. The next prime is 20251904591. The reversal of 20251904581 is 18540915202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20205201025 + 46703556 = 142145^2 + 6834^2 .

It is a cyclic number.

It is not a de Polignac number, because 20251904581 - 2¹⁹ = 20251380293 is a prime.

It is a super-2 number, since 2×20251904581² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20251904581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20251904591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10125952290 + 10125952291.

It is an arithmetic number, because the mean of its divisors is an integer number (10125952291).

Almost surely, 2^20251904581 is an apocalyptic number.

It is an amenable number.

20251904581 is a deficient number, since it is larger than the sum of its proper divisors (1).

20251904581 is an equidigital number, since it uses as much as digits as its factorization.

20251904581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28800, while the sum is 37.

The spelling of 20251904581 in words is "twenty billion, two hundred fifty-one million, nine hundred four thousand, five hundred eighty-one".