25779991 has 8 divisors (see below), whose sum is σ = 26553600. Its totient is φ = 25017720.

The previous prime is 25779977. The next prime is 25779997. The reversal of 25779991 is 19997752.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 25779991 - 2⁷ = 25779863 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 (25779997) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1896 + ... + 7426.

It is an arithmetic number, because the mean of its divisors is an integer number (3319200).

Almost surely, 2^25779991 is an apocalyptic number.

25779991 is a deficient number, since it is larger than the sum of its proper divisors (773609).

25779991 is an equidigital number, since it uses as much as digits as its factorization.

25779991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5669.

The product of its digits is 357210, while the sum is 49.

The square root of 25779991 is about 5077.4000236341. The cubic root of 25779991 is about 295.4116287558.

The spelling of 25779991 in words is "twenty-five million, seven hundred seventy-nine thousand, nine hundred ninety-one".