1991141807 has 2 divisors, whose sum is σ = 1991141808. Its totient is φ = 1991141806.

The previous prime is 1991141797. The next prime is 1991141819. The reversal of 1991141807 is 7081411991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1991141807 - 2¹⁶ = 1991076271 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1991141837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995570903 + 995570904.

It is an arithmetic number, because the mean of its divisors is an integer number (995570904).

Almost surely, 2^1991141807 is an apocalyptic number.

1991141807 is a deficient number, since it is larger than the sum of its proper divisors (1).

1991141807 is an equidigital number, since it uses as much as digits as its factorization.

1991141807 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 41.

The square root of 1991141807 is about 44622.2120361597. The cubic root of 1991141807 is about 1258.0581929534.

The spelling of 1991141807 in words is "one billion, nine hundred ninety-one million, one hundred forty-one thousand, eight hundred seven".