25550520491 has 2 divisors, whose sum is σ = 25550520492. Its totient is φ = 25550520490.

The previous prime is 25550520431. The next prime is 25550520517. The reversal of 25550520491 is 19402505552.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25550520491 is a prime.

It is a super-2 number, since 2×25550520491² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (25550520421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12775260245 + 12775260246.

It is an arithmetic number, because the mean of its divisors is an integer number (12775260246).

Almost surely, 2^25550520491 is an apocalyptic number.

25550520491 is a deficient number, since it is larger than the sum of its proper divisors (1).

25550520491 is an equidigital number, since it uses as much as digits as its factorization.

25550520491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90000, while the sum is 38.

The spelling of 25550520491 in words is "twenty-five billion, five hundred fifty million, five hundred twenty thousand, four hundred ninety-one".