25508257581 has 16 divisors (see below), whose sum is σ = 35188329600. Its totient is φ = 16416996288.

The previous prime is 25508257553. The next prime is 25508257613. The reversal of 25508257581 is 18575280552.

It is not a de Polignac number, because 25508257581 - 2¹¹ = 25508255533 is a prime.

It is a super-2 number, since 2×25508257581² (a number of 22 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 25508257581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25508257531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 939880 + ... + 966638.

It is an arithmetic number, because the mean of its divisors is an integer number (2199270600).

Almost surely, 2^25508257581 is an apocalyptic number.

It is an amenable number.

25508257581 is a deficient number, since it is larger than the sum of its proper divisors (9680072019).

25508257581 is a wasteful number, since it uses less digits than its factorization.

25508257581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37748.

The product of its (nonzero) digits is 1120000, while the sum is 48.

The spelling of 25508257581 in words is "twenty-five billion, five hundred eight million, two hundred fifty-seven thousand, five hundred eighty-one".