25686991 has 8 divisors (see below), whose sum is σ = 28779984. Its totient is φ = 22720320.

The previous prime is 25686989. The next prime is 25687009. The reversal of 25686991 is 19968652.

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

It is a cyclic number.

It is not a de Polignac number, because 25686991 - 2¹ = 25686989 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25686911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31150 + ... + 31963.

It is an arithmetic number, because the mean of its divisors is an integer number (3597498).

Almost surely, 2^25686991 is an apocalyptic number.

25686991 is a deficient number, since it is larger than the sum of its proper divisors (3092993).

25686991 is a wasteful number, since it uses less digits than its factorization.

25686991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63161.

The product of its digits is 233280, while the sum is 46.

The square root of 25686991 is about 5068.2335186927. The cubic root of 25686991 is about 295.0559732916.

It can be divided in two parts, 2568 and 6991, that added together give a palindrome (9559).

The spelling of 25686991 in words is "twenty-five million, six hundred eighty-six thousand, nine hundred ninety-one".