25018778261 has 4 divisors (see below), whose sum is σ = 25020234912. Its totient is φ = 25017321612.

The previous prime is 25018778249. The next prime is 25018778293. The reversal of 25018778261 is 16287781052.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25018778261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25018778201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 702251 + ... + 737016.

It is an arithmetic number, because the mean of its divisors is an integer number (6255058728).

Almost surely, 2^25018778261 is an apocalyptic number.

It is an amenable number.

25018778261 is a deficient number, since it is larger than the sum of its proper divisors (1456651).

25018778261 is a wasteful number, since it uses less digits than its factorization.

25018778261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1456650.

The product of its (nonzero) digits is 376320, while the sum is 47.

The spelling of 25018778261 in words is "twenty-five billion, eighteen million, seven hundred seventy-eight thousand, two hundred sixty-one".