25899991 has 4 divisors (see below), whose sum is σ = 27892312. Its totient is φ = 23907672.

The previous prime is 25899971. The next prime is 25900013. The reversal of 25899991 is 19999852.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 25899991 - 2⁹ = 25899479 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 (25899931) 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, 996141 + ... + 996166.

It is an arithmetic number, because the mean of its divisors is an integer number (6973078).

Almost surely, 2^25899991 is an apocalyptic number.

25899991 is a deficient number, since it is larger than the sum of its proper divisors (1992321).

25899991 is a wasteful number, since it uses less digits than its factorization.

25899991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1992320.

The product of its digits is 524880, while the sum is 52.

The square root of 25899991 is about 5089.2033757750. The cubic root of 25899991 is about 295.8692774065.

The spelling of 25899991 in words is "twenty-five million, eight hundred ninety-nine thousand, nine hundred ninety-one".