25864542109 has 4 divisors (see below), whose sum is σ = 29559476704. Its totient is φ = 22169607516.

The previous prime is 25864542079. The next prime is 25864542113. The reversal of 25864542109 is 90124546852.

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 not a de Polignac number, because 25864542109 - 2¹⁷ = 25864411037 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 (25864548109) 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, 1847467287 + ... + 1847467300.

It is an arithmetic number, because the mean of its divisors is an integer number (7389869176).

Almost surely, 2^25864542109 is an apocalyptic number.

It is an amenable number.

25864542109 is a deficient number, since it is larger than the sum of its proper divisors (3694934595).

25864542109 is an equidigital number, since it uses as much as digits as its factorization.

25864542109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3694934594.

The product of its (nonzero) digits is 691200, while the sum is 46.

The spelling of 25864542109 in words is "twenty-five billion, eight hundred sixty-four million, five hundred forty-two thousand, one hundred nine".