801220991 has 2 divisors, whose sum is σ = 801220992. Its totient is φ = 801220990.

The previous prime is 801220969. The next prime is 801220993. The reversal of 801220991 is 199022108.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 801220991 - 2¹⁰ = 801219967 is a prime.

It is a Sophie Germain prime.

Together with 801220993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (801220993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 400610495 + 400610496.

It is an arithmetic number, because the mean of its divisors is an integer number (400610496).

Almost surely, 2^801220991 is an apocalyptic number.

801220991 is a deficient number, since it is larger than the sum of its proper divisors (1).

801220991 is an equidigital number, since it uses as much as digits as its factorization.

801220991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 801220991 is about 28305.8472934480. The cubic root of 801220991 is about 928.7898048390.

The spelling of 801220991 in words is "eight hundred one million, two hundred twenty thousand, nine hundred ninety-one".