25405321004561 has 4 divisors (see below), whose sum is σ = 26024962980324. Its totient is φ = 24785679028800.

The previous prime is 25405321004551. The next prime is 25405321004587. The reversal of 25405321004561 is 16540012350452.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 874786090000 + 24530534914561 = 935300^2 + 4952831^2 .

It is not a de Polignac number, because 25405321004561 - 2³⁴ = 25388141135377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25405321004551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 309820987820 + ... + 309820987901.

It is an arithmetic number, because the mean of its divisors is an integer number (6506240745081).

Almost surely, 2^{25405321004561} is an apocalyptic number.

It is an amenable number.

25405321004561 is a deficient number, since it is larger than the sum of its proper divisors (619641975763).

25405321004561 is an equidigital number, since it uses as much as digits as its factorization.

25405321004561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619641975762.

The product of its (nonzero) digits is 144000, while the sum is 38.

The spelling of 25405321004561 in words is "twenty-five trillion, four hundred five billion, three hundred twenty-one million, four thousand, five hundred sixty-one".