25681665025 has 9 divisors (see below), whose sum is σ = 31846258243. Its totient is φ = 20544691000.

The previous prime is 25681664951. The next prime is 25681665029. The reversal of 25681665025 is 52056618652.

The square root of 25681665025 is 160255.

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

It can be written as a sum of positive squares in only one way, i.e., 9245399409 + 16436265616 = 96153^2 + 128204^2 .

It is not a de Polignac number, because 25681665025 - 2⁹ = 25681664513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25681665029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 785250 + ... + 817300.

Almost surely, 2^25681665025 is an apocalyptic number.

25681665025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

25681665025 is the 160255-th square number.

25681665025 is the 80128-th centered octagonal number.

It is an amenable number.

25681665025 is a deficient number, since it is larger than the sum of its proper divisors (6164593218).

25681665025 is an frugal number, since it uses more digits than its factorization.

25681665025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64112 (or 32056 counting only the distinct ones).

The product of its (nonzero) digits is 864000, while the sum is 46.

The spelling of 25681665025 in words is "twenty-five billion, six hundred eighty-one million, six hundred sixty-five thousand, twenty-five".