25515555617 has 6 divisors (see below), whose sum is σ = 25940704374. Its totient is φ = 25097264160.

The previous prime is 25515555599. The next prime is 25515555641. The reversal of 25515555617 is 71655551552.

It can be written as a sum of positive squares in 3 ways, for example, as 362864401 + 25152691216 = 19049^2 + 158596^2 .

It is not a de Polignac number, because 25515555617 - 2¹⁶ = 25515490081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25515552617) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3424868 + ... + 3432309.

It is an arithmetic number, because the mean of its divisors is an integer number (4323450729).

Almost surely, 2^25515555617 is an apocalyptic number.

It is an amenable number.

25515555617 is a deficient number, since it is larger than the sum of its proper divisors (425148757).

25515555617 is an frugal number, since it uses more digits than its factorization.

25515555617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6857299 (or 6857238 counting only the distinct ones).

The product of its digits is 1312500, while the sum is 47.

The spelling of 25515555617 in words is "twenty-five billion, five hundred fifteen million, five hundred fifty-five thousand, six hundred seventeen".