25801991 has 2 divisors, whose sum is σ = 25801992. Its totient is φ = 25801990.

The previous prime is 25801973. The next prime is 25802009. The reversal of 25801991 is 19910852.

It is a balanced prime because it is at equal distance from previous prime (25801973) and next prime (25802009).

It is a cyclic number.

It is not a de Polignac number, because 25801991 - 2⁶ = 25801927 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25801921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12900995 + 12900996.

It is an arithmetic number, because the mean of its divisors is an integer number (12900996).

Almost surely, 2^25801991 is an apocalyptic number.

25801991 is a deficient number, since it is larger than the sum of its proper divisors (1).

25801991 is an equidigital number, since it uses as much as digits as its factorization.

25801991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 35.

The square root of 25801991 is about 5079.5660247702. The cubic root of 25801991 is about 295.4956371637.

The spelling of 25801991 in words is "twenty-five million, eight hundred one thousand, nine hundred ninety-one".