25681421 has 4 divisors (see below), whose sum is σ = 25742844. Its totient is φ = 25620000.

The previous prime is 25681393. The next prime is 25681451. The reversal of 25681421 is 12418652.

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 6056521 + 19624900 = 2461^2 + 4430^2 .

It is a cyclic number.

It is not a de Polignac number, because 25681421 - 2²² = 21487117 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 (25681451) 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, 30080 + ... + 30921.

It is an arithmetic number, because the mean of its divisors is an integer number (6435711).

Almost surely, 2^25681421 is an apocalyptic number.

It is an amenable number.

25681421 is a deficient number, since it is larger than the sum of its proper divisors (61423).

25681421 is an equidigital number, since it uses as much as digits as its factorization.

25681421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61422.

The product of its digits is 3840, while the sum is 29.

The square root of 25681421 is about 5067.6839877798. The cubic root of 25681421 is about 295.0346449783.

The spelling of 25681421 in words is "twenty-five million, six hundred eighty-one thousand, four hundred twenty-one".