25217255781 has 12 divisors (see below), whose sum is σ = 36449244000. Its totient is φ = 16800279720.

The previous prime is 25217255759. The next prime is 25217255801. The reversal of 25217255781 is 18755271252.

25217255781 is a `hidden beast` number, since 2 + 5 + 2 + 1 + 72 + 5 + 578 + 1 = 666.

It is not a de Polignac number, because 25217255781 - 2¹⁰ = 25217254757 is a prime.

It is a super-2 number, since 2×25217255781² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25217255741) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 921105 + ... + 948086.

It is an arithmetic number, because the mean of its divisors is an integer number (3037437000).

Almost surely, 2^25217255781 is an apocalyptic number.

It is an amenable number.

25217255781 is a deficient number, since it is larger than the sum of its proper divisors (11231988219).

25217255781 is a wasteful number, since it uses less digits than its factorization.

25217255781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1870696 (or 1870693 counting only the distinct ones).

The product of its digits is 392000, while the sum is 45.

The spelling of 25217255781 in words is "twenty-five billion, two hundred seventeen million, two hundred fifty-five thousand, seven hundred eighty-one".