25564646449 has 2 divisors, whose sum is σ = 25564646450. Its totient is φ = 25564646448.

The previous prime is 25564646413. The next prime is 25564646557. The reversal of 25564646449 is 94464646552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18283096225 + 7281550224 = 135215^2 + 85332^2 .

It is a cyclic number.

It is not a de Polignac number, because 25564646449 - 2¹³ = 25564638257 is a prime.

It is a super-2 number, since 2×25564646449² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 25564646449.

It is not a weakly prime, because it can be changed into another prime (25564646749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12782323224 + 12782323225.

It is an arithmetic number, because the mean of its divisors is an integer number (12782323225).

Almost surely, 2^25564646449 is an apocalyptic number.

It is an amenable number.

25564646449 is a deficient number, since it is larger than the sum of its proper divisors (1).

25564646449 is an equidigital number, since it uses as much as digits as its factorization.

25564646449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24883200, while the sum is 55.

The spelling of 25564646449 in words is "twenty-five billion, five hundred sixty-four million, six hundred forty-six thousand, four hundred forty-nine".