25001681 has 2 divisors, whose sum is σ = 25001682. Its totient is φ = 25001680.

The previous prime is 25001671. The next prime is 25001687. The reversal of 25001681 is 18610052.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25000000 + 1681 = 5000^2 + 41^2 .

It is a cyclic number.

It is not a de Polignac number, because 25001681 - 2⁶ = 25001617 is a prime.

It is a super-2 number, since 2×25001681² = 1250168105651522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (25001687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12500840 + 12500841.

It is an arithmetic number, because the mean of its divisors is an integer number (12500841).

Almost surely, 2^25001681 is an apocalyptic number.

It is an amenable number.

25001681 is a deficient number, since it is larger than the sum of its proper divisors (1).

25001681 is an equidigital number, since it uses as much as digits as its factorization.

25001681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 25001681 is about 5000.1680971743. The cubic root of 25001681 is about 292.4083273728.

It can be divided in two parts, 2500 and 1681, that multiplied together give a square (4202500 = 2050²).

The spelling of 25001681 in words is "twenty-five million, one thousand, six hundred eighty-one".