25865489781 has 16 divisors (see below), whose sum is σ = 38780925120. Its totient is φ = 17035903440.

The previous prime is 25865489761. The next prime is 25865489801. The reversal of 25865489781 is 18798456852.

25865489781 is a `hidden beast` number, since 2 + 5 + 8 + 6 + 548 + 9 + 7 + 81 = 666.

It is an interprime number because it is at equal distance from previous prime (25865489761) and next prime (25865489801).

It is not a de Polignac number, because 25865489781 - 2⁶ = 25865489717 is a prime.

It is a super-2 number, since 2×25865489781² (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 (25865489761) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5768730 + ... + 5773211.

It is an arithmetic number, because the mean of its divisors is an integer number (2423807820).

Almost surely, 2^25865489781 is an apocalyptic number.

It is an amenable number.

25865489781 is a deficient number, since it is larger than the sum of its proper divisors (12915435339).

25865489781 is a wasteful number, since it uses less digits than its factorization.

25865489781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11542033 (or 11542027 counting only the distinct ones).

The product of its digits is 38707200, while the sum is 63.

The spelling of 25865489781 in words is "twenty-five billion, eight hundred sixty-five million, four hundred eighty-nine thousand, seven hundred eighty-one".