991722159 has 12 divisors (see below), whose sum is σ = 1433957616. Its totient is φ = 660469632.

The previous prime is 991722143. The next prime is 991722161. The reversal of 991722159 is 951227199.

It is not a de Polignac number, because 991722159 - 2⁴ = 991722143 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991722169) 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 in 11 ways as a sum of consecutive naturals, for example, 47202 + ... + 64895.

It is an arithmetic number, because the mean of its divisors is an integer number (119496468).

Almost surely, 2^991722159 is an apocalyptic number.

991722159 is a deficient number, since it is larger than the sum of its proper divisors (442235457).

991722159 is a wasteful number, since it uses less digits than its factorization.

991722159 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113086 (or 113083 counting only the distinct ones).

The product of its digits is 102060, while the sum is 45.

The square root of 991722159 is about 31491.6204568771. The cubic root of 991722159 is about 997.2330708307.

The spelling of 991722159 in words is "nine hundred ninety-one million, seven hundred twenty-two thousand, one hundred fifty-nine".