25801206991 has 8 divisors (see below), whose sum is σ = 29493046400. Its totient is φ = 22110855768.

The previous prime is 25801206931. The next prime is 25801207001. The reversal of 25801206991 is 19960210852.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25801206991 is a prime.

It is a super-3 number, since 3×25801206991³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25801206931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 334641 + ... + 404458.

It is an arithmetic number, because the mean of its divisors is an integer number (3686630800).

Almost surely, 2^25801206991 is an apocalyptic number.

25801206991 is a deficient number, since it is larger than the sum of its proper divisors (3691839409).

25801206991 is an equidigital number, since it uses as much as digits as its factorization.

25801206991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 744093.

The product of its (nonzero) digits is 77760, while the sum is 43.

The spelling of 25801206991 in words is "twenty-five billion, eight hundred one million, two hundred six thousand, nine hundred ninety-one".