25643821205 has 16 divisors (see below), whose sum is σ = 31494074304. Its totient is φ = 20034241920.

The previous prime is 25643821193. The next prime is 25643821211. The reversal of 25643821205 is 50212834652.

It is a happy number.

It is not a de Polignac number, because 25643821205 - 2²⁴ = 25627043989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1980362 + ... + 1993268.

It is an arithmetic number, because the mean of its divisors is an integer number (1968379644).

Almost surely, 2^25643821205 is an apocalyptic number.

It is an amenable number.

25643821205 is a deficient number, since it is larger than the sum of its proper divisors (5850253099).

25643821205 is a wasteful number, since it uses less digits than its factorization.

25643821205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22196.

The product of its (nonzero) digits is 115200, while the sum is 38.

The spelling of 25643821205 in words is "twenty-five billion, six hundred forty-three million, eight hundred twenty-one thousand, two hundred five".