25347505681 has 3 divisors (see below), whose sum is σ = 25347664891. Its totient is φ = 25347346472.

The previous prime is 25347505661. The next prime is 25347505721. The reversal of 25347505681 is 18650574352.

The square root of 25347505681 is 159209.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 24338808081 + 1008697600 = 156009^2 + 31760^2 .

It is not a de Polignac number, because 25347505681 - 2⁷ = 25347505553 is a prime.

It is a super-2 number, since 2×25347505681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25347505661) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 79605 + ... + 238813.

Almost surely, 2^25347505681 is an apocalyptic number.

25347505681 is the 159209-th square number.

25347505681 is the 79605-th centered octagonal number.

It is an amenable number.

25347505681 is a deficient number, since it is larger than the sum of its proper divisors (159210).

25347505681 is an frugal number, since it uses more digits than its factorization.

25347505681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318418 (or 159209 counting only the distinct ones).

The product of its (nonzero) digits is 1008000, while the sum is 46.

The spelling of 25347505681 in words is "twenty-five billion, three hundred forty-seven million, five hundred five thousand, six hundred eighty-one".