25291284581 has 2 divisors, whose sum is σ = 25291284582. Its totient is φ = 25291284580.

The previous prime is 25291284467. The next prime is 25291284583. The reversal of 25291284581 is 18548219252.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21203728225 + 4087556356 = 145615^2 + 63934^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25291284581 is a prime.

It is a super-2 number, since 2×25291284581² (a number of 22 digits) contains 22 as substring.

Together with 25291284583, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25291284583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12645642290 + 12645642291.

It is an arithmetic number, because the mean of its divisors is an integer number (12645642291).

Almost surely, 2^25291284581 is an apocalyptic number.

It is an amenable number.

25291284581 is a deficient number, since it is larger than the sum of its proper divisors (1).

25291284581 is an equidigital number, since it uses as much as digits as its factorization.

25291284581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 460800, while the sum is 47.

The spelling of 25291284581 in words is "twenty-five billion, two hundred ninety-one million, two hundred eighty-four thousand, five hundred eighty-one".