25897717949 has 4 divisors (see below), whose sum is σ = 26154131100. Its totient is φ = 25641304800.

The previous prime is 25897717921. The next prime is 25897717957. The reversal of 25897717949 is 94971779852.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 24769093924 + 1128624025 = 157382^2 + 33595^2 .

It is a cyclic number.

It is not a de Polignac number, because 25897717949 - 2⁸ = 25897717693 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 (25897717049) 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, 128206424 + ... + 128206625.

It is an arithmetic number, because the mean of its divisors is an integer number (6538532775).

Almost surely, 2^25897717949 is an apocalyptic number.

It is an amenable number.

25897717949 is a deficient number, since it is larger than the sum of its proper divisors (256413151).

25897717949 is a wasteful number, since it uses less digits than its factorization.

25897717949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256413150.

The product of its digits is 80015040, while the sum is 68.

The spelling of 25897717949 in words is "twenty-five billion, eight hundred ninety-seven million, seven hundred seventeen thousand, nine hundred forty-nine".