25640831 has 2 divisors, whose sum is σ = 25640832. Its totient is φ = 25640830.

The previous prime is 25640809. The next prime is 25640863. The reversal of 25640831 is 13804652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 25640831 - 2¹⁸ = 25378687 is a prime.

It is a super-2 number, since 2×25640831² = 1314904428741122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 25640794 and 25640803.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25643831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12820415 + 12820416.

It is an arithmetic number, because the mean of its divisors is an integer number (12820416).

Almost surely, 2^25640831 is an apocalyptic number.

25640831 is a deficient number, since it is larger than the sum of its proper divisors (1).

25640831 is an equidigital number, since it uses as much as digits as its factorization.

25640831 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 25640831 is about 5063.6776161205. The cubic root of 25640831 is about 294.8791269622.

The spelling of 25640831 in words is "twenty-five million, six hundred forty thousand, eight hundred thirty-one".