25101991 has 2 divisors, whose sum is σ = 25101992. Its totient is φ = 25101990.

The previous prime is 25101977. The next prime is 25101997. The reversal of 25101991 is 19910152.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 25101991 - 2⁵ = 25101959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25101997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12550995 + 12550996.

It is an arithmetic number, because the mean of its divisors is an integer number (12550996).

Almost surely, 2^25101991 is an apocalyptic number.

25101991 is a deficient number, since it is larger than the sum of its proper divisors (1).

25101991 is an equidigital number, since it uses as much as digits as its factorization.

25101991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 810, while the sum is 28.

The square root of 25101991 is about 5010.1887190005. The cubic root of 25101991 is about 292.7988656368.

The spelling of 25101991 in words is "twenty-five million, one hundred one thousand, nine hundred ninety-one".