991883773 has 2 divisors, whose sum is σ = 991883774. Its totient is φ = 991883772.

The previous prime is 991883749. The next prime is 991883779. The reversal of 991883773 is 377388199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 876041604 + 115842169 = 29598^2 + 10763^2 .

It is a cyclic number.

It is not a de Polignac number, because 991883773 - 2²¹ = 989786621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991883779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495941886 + 495941887.

It is an arithmetic number, because the mean of its divisors is an integer number (495941887).

Almost surely, 2^991883773 is an apocalyptic number.

It is an amenable number.

991883773 is a deficient number, since it is larger than the sum of its proper divisors (1).

991883773 is an equidigital number, since it uses as much as digits as its factorization.

991883773 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2286144, while the sum is 55.

The square root of 991883773 is about 31494.1863365288. The cubic root of 991883773 is about 997.2872385799.

The spelling of 991883773 in words is "nine hundred ninety-one million, eight hundred eighty-three thousand, seven hundred seventy-three".