991610801 has 2 divisors, whose sum is σ = 991610802. Its totient is φ = 991610800.

The previous prime is 991610791. The next prime is 991610803. The reversal of 991610801 is 108016199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 884467600 + 107143201 = 29740^2 + 10351^2 .

It is a cyclic number.

It is not a de Polignac number, because 991610801 - 2²⁶ = 924501937 is a prime.

Together with 991610803, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (991610803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495805400 + 495805401.

It is an arithmetic number, because the mean of its divisors is an integer number (495805401).

Almost surely, 2^991610801 is an apocalyptic number.

It is an amenable number.

991610801 is a deficient number, since it is larger than the sum of its proper divisors (1).

991610801 is an equidigital number, since it uses as much as digits as its factorization.

991610801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 35.

The square root of 991610801 is about 31489.8523496062. The cubic root of 991610801 is about 997.1957438314.

The spelling of 991610801 in words is "nine hundred ninety-one million, six hundred ten thousand, eight hundred one".