5245561991 has 2 divisors, whose sum is σ = 5245561992. Its totient is φ = 5245561990.

The previous prime is 5245561943. The next prime is 5245562027. The reversal of 5245561991 is 1991655425.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 5245561991 - 2²⁶ = 5178453127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5245561921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2622780995 + 2622780996.

It is an arithmetic number, because the mean of its divisors is an integer number (2622780996).

Almost surely, 2^5245561991 is an apocalyptic number.

5245561991 is a deficient number, since it is larger than the sum of its proper divisors (1).

5245561991 is an equidigital number, since it uses as much as digits as its factorization.

5245561991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 486000, while the sum is 47.

The square root of 5245561991 is about 72426.2520844479. The cubic root of 5245561991 is about 1737.5234498569.

The spelling of 5245561991 in words is "five billion, two hundred forty-five million, five hundred sixty-one thousand, nine hundred ninety-one".