25664878381 has 4 divisors (see below), whose sum is σ = 25799249664. Its totient is φ = 25530507100.

The previous prime is 25664878373. The next prime is 25664878397. The reversal of 25664878381 is 18387846652.

It is a happy number.

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 not a de Polignac number, because 25664878381 - 2³ = 25664878373 is a prime.

It is a super-2 number, since 2×25664878381² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25664878301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67185355 + ... + 67185736.

It is an arithmetic number, because the mean of its divisors is an integer number (6449812416).

Almost surely, 2^25664878381 is an apocalyptic number.

It is an amenable number.

25664878381 is a deficient number, since it is larger than the sum of its proper divisors (134371283).

25664878381 is a wasteful number, since it uses less digits than its factorization.

25664878381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134371282.

The product of its digits is 15482880, while the sum is 58.

The spelling of 25664878381 in words is "twenty-five billion, six hundred sixty-four million, eight hundred seventy-eight thousand, three hundred eighty-one".