25564646551 has 8 divisors (see below), whose sum is σ = 25667533440. Its totient is φ = 25461928248.

The previous prime is 25564646449. The next prime is 25564646557. The reversal of 25564646551 is 15564646552.

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 25564646551 - 2¹⁵ = 25564613783 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 25564646495 and 25564646504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25564646557) 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, 266260 + ... + 349318.

It is an arithmetic number, because the mean of its divisors is an integer number (3208441680).

Almost surely, 2^25564646551 is an apocalyptic number.

25564646551 is a deficient number, since it is larger than the sum of its proper divisors (102886889).

25564646551 is an equidigital number, since it uses as much as digits as its factorization.

25564646551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84293.

The product of its digits is 4320000, while the sum is 49.

Subtracting from 25564646551 its reverse (15564646552), we obtain a palindrome (9999999999).

The spelling of 25564646551 in words is "twenty-five billion, five hundred sixty-four million, six hundred forty-six thousand, five hundred fifty-one".