25555555549 has 2 divisors, whose sum is σ = 25555555550. Its totient is φ = 25555555548.

The previous prime is 25555555489. The next prime is 25555555573. The reversal of 25555555549 is 94555555552.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14198390649 + 11357164900 = 119157^2 + 106570^2 .

It is a cyclic number.

It is not a de Polignac number, because 25555555549 - 2⁹ = 25555555037 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 25555555549.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25555555349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12777777774 + 12777777775.

It is an arithmetic number, because the mean of its divisors is an integer number (12777777775).

Almost surely, 2^25555555549 is an apocalyptic number.

It is an amenable number.

25555555549 is a deficient number, since it is larger than the sum of its proper divisors (1).

25555555549 is an equidigital number, since it uses as much as digits as its factorization.

25555555549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28125000, while the sum is 55.

The spelling of 25555555549 in words is "twenty-five billion, five hundred fifty-five million, five hundred fifty-five thousand, five hundred forty-nine".