25221207581 has 2 divisors, whose sum is σ = 25221207582. Its totient is φ = 25221207580.

The previous prime is 25221207541. The next prime is 25221207623. The reversal of 25221207581 is 18570212252.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25174899556 + 46308025 = 158666^2 + 6805^2 .

It is a cyclic number.

It is not a de Polignac number, because 25221207581 - 2¹⁴ = 25221191197 is a prime.

It is a super-2 number, since 2×25221207581² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25221207541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12610603790 + 12610603791.

It is an arithmetic number, because the mean of its divisors is an integer number (12610603791).

Almost surely, 2^25221207581 is an apocalyptic number.

It is an amenable number.

25221207581 is a deficient number, since it is larger than the sum of its proper divisors (1).

25221207581 is an equidigital number, since it uses as much as digits as its factorization.

25221207581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22400, while the sum is 35.

The spelling of 25221207581 in words is "twenty-five billion, two hundred twenty-one million, two hundred seven thousand, five hundred eighty-one".