5205081991 has 2 divisors, whose sum is σ = 5205081992. Its totient is φ = 5205081990.

The previous prime is 5205081971. The next prime is 5205082013. The reversal of 5205081991 is 1991805025.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 5205081991 - 2¹³ = 5205073799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5205081941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2602540995 + 2602540996.

It is an arithmetic number, because the mean of its divisors is an integer number (2602540996).

Almost surely, 2^5205081991 is an apocalyptic number.

5205081991 is a deficient number, since it is larger than the sum of its proper divisors (1).

5205081991 is an equidigital number, since it uses as much as digits as its factorization.

5205081991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32400, while the sum is 40.

The square root of 5205081991 is about 72146.2541716477. The cubic root of 5205081991 is about 1733.0424140165.

The spelling of 5205081991 in words is "five billion, two hundred five million, eighty-one thousand, nine hundred ninety-one".