25640807 has 2 divisors, whose sum is σ = 25640808. Its totient is φ = 25640806.

The previous prime is 25640789. The next prime is 25640809. The reversal of 25640807 is 70804652.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 25640807 - 2¹⁸ = 25378663 is a prime.

It is a super-2 number, since 2×25640807² = 1314901967222498, which contains 22 as substring.

Together with 25640809, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25640809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12820403 + 12820404.

It is an arithmetic number, because the mean of its divisors is an integer number (12820404).

Almost surely, 2^25640807 is an apocalyptic number.

25640807 is a deficient number, since it is larger than the sum of its proper divisors (1).

25640807 is an equidigital number, since it uses as much as digits as its factorization.

25640807 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13440, while the sum is 32.

The square root of 25640807 is about 5063.6752463009. The cubic root of 25640807 is about 294.8790349592.

The spelling of 25640807 in words is "twenty-five million, six hundred forty thousand, eight hundred seven".