25555555055491 has 2 divisors, whose sum is σ = 25555555055492. Its totient is φ = 25555555055490.

The previous prime is 25555555055461. The next prime is 25555555055543. The reversal of 25555555055491 is 19455055555552.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 25555555055491 - 2³⁷ = 25418116102019 is a prime.

It is not a weakly prime, because it can be changed into another prime (25555555055461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12777777527745 + 12777777527746.

It is an arithmetic number, because the mean of its divisors is an integer number (12777777527746).

Almost surely, 2^{25555555055491} is an apocalyptic number.

25555555055491 is a deficient number, since it is larger than the sum of its proper divisors (1).

25555555055491 is an equidigital number, since it uses as much as digits as its factorization.

25555555055491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 140625000, while the sum is 61.

The spelling of 25555555055491 in words is "twenty-five trillion, five hundred fifty-five billion, five hundred fifty-five million, fifty-five thousand, four hundred ninety-one".