25121501613 has 24 divisors (see below), whose sum is σ = 41376594168. Its totient is φ = 14550008832.

The previous prime is 25121501609. The next prime is 25121501621. The reversal of 25121501613 is 31610512152.

25121501613 is a `hidden beast` number, since 25 + 1 + 21 + 5 + 0 + 1 + 613 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 753667209 + 24367834404 = 27453^2 + 156102^2 .

It is not a de Polignac number, because 25121501613 - 2² = 25121501609 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25121501663) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6313120 + ... + 6317097.

It is an arithmetic number, because the mean of its divisors is an integer number (1724024757).

Almost surely, 2^25121501613 is an apocalyptic number.

It is an amenable number.

25121501613 is a deficient number, since it is larger than the sum of its proper divisors (16255092555).

25121501613 is a wasteful number, since it uses less digits than its factorization.

25121501613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12630253 (or 12630250 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The spelling of 25121501613 in words is "twenty-five billion, one hundred twenty-one million, five hundred one thousand, six hundred thirteen".