25195921817 has 4 divisors (see below), whose sum is σ = 27486460176. Its totient is φ = 22905383460.

The previous prime is 25195921771. The next prime is 25195921837. The reversal of 25195921817 is 71812959152.

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 25195921817 - 2⁶ = 25195921753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25195921837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1145269163 + ... + 1145269184.

It is an arithmetic number, because the mean of its divisors is an integer number (6871615044).

Almost surely, 2^25195921817 is an apocalyptic number.

It is an amenable number.

25195921817 is a deficient number, since it is larger than the sum of its proper divisors (2290538359).

25195921817 is a wasteful number, since it uses less digits than its factorization.

25195921817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2290538358.

The product of its digits is 453600, while the sum is 50.

The spelling of 25195921817 in words is "twenty-five billion, one hundred ninety-five million, nine hundred twenty-one thousand, eight hundred seventeen".