991845377 has 2 divisors, whose sum is σ = 991845378. Its totient is φ = 991845376.

The previous prime is 991845367. The next prime is 991845389. The reversal of 991845377 is 773548199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 921972496 + 69872881 = 30364^2 + 8359^2 .

It is a cyclic number.

It is not a de Polignac number, because 991845377 - 2⁸ = 991845121 is a prime.

It is not a weakly prime, because it can be changed into another prime (991845317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495922688 + 495922689.

It is an arithmetic number, because the mean of its divisors is an integer number (495922689).

Almost surely, 2^991845377 is an apocalyptic number.

It is an amenable number.

991845377 is a deficient number, since it is larger than the sum of its proper divisors (1).

991845377 is an equidigital number, since it uses as much as digits as its factorization.

991845377 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1905120, while the sum is 53.

The square root of 991845377 is about 31493.5767578089. The cubic root of 991845377 is about 997.2743700242.

The spelling of 991845377 in words is "nine hundred ninety-one million, eight hundred forty-five thousand, three hundred seventy-seven".