909791021 has 2 divisors, whose sum is σ = 909791022. Its totient is φ = 909791020.

The previous prime is 909791011. The next prime is 909791093. The reversal of 909791021 is 120197909.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 751308100 + 158482921 = 27410^2 + 12589^2 .

It is a cyclic number.

It is not a de Polignac number, because 909791021 - 2¹⁸ = 909528877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (909791011) 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, 454895510 + 454895511.

It is an arithmetic number, because the mean of its divisors is an integer number (454895511).

Almost surely, 2^909791021 is an apocalyptic number.

It is an amenable number.

909791021 is a deficient number, since it is larger than the sum of its proper divisors (1).

909791021 is an equidigital number, since it uses as much as digits as its factorization.

909791021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10206, while the sum is 38.

The square root of 909791021 is about 30162.7422659147. The cubic root of 909791021 is about 968.9779226127.

The spelling of 909791021 in words is "nine hundred nine million, seven hundred ninety-one thousand, twenty-one".