25694705521 has 2 divisors, whose sum is σ = 25694705522. Its totient is φ = 25694705520.

The previous prime is 25694705503. The next prime is 25694705593. The reversal of 25694705521 is 12550749652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17413705521 + 8281000000 = 131961^2 + 91000^2 .

It is a cyclic number.

It is not a de Polignac number, because 25694705521 - 2¹⁵ = 25694672753 is a prime.

It is not a weakly prime, because it can be changed into another prime (25694705501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12847352760 + 12847352761.

It is an arithmetic number, because the mean of its divisors is an integer number (12847352761).

Almost surely, 2^25694705521 is an apocalyptic number.

It is an amenable number.

25694705521 is a deficient number, since it is larger than the sum of its proper divisors (1).

25694705521 is an equidigital number, since it uses as much as digits as its factorization.

25694705521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 756000, while the sum is 46.

The spelling of 25694705521 in words is "twenty-five billion, six hundred ninety-four million, seven hundred five thousand, five hundred twenty-one".