991173222 has 24 divisors (see below), whose sum is σ = 2312738064. Its totient is φ = 304976304.

The previous prime is 991173203. The next prime is 991173241. The reversal of 991173222 is 222371199.

It is an interprime number because it is at equal distance from previous prime (991173203) and next prime (991173241).

It is a super-2 number, since 2×991173222² = 1964848712019722568, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2117658 + ... + 2118125.

It is an arithmetic number, because the mean of its divisors is an integer number (96364086).

Almost surely, 2^991173222 is an apocalyptic number.

991173222 is an abundant number, since it is smaller than the sum of its proper divisors (1321564842).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991173222 is a wasteful number, since it uses less digits than its factorization.

991173222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4235804 (or 4235801 counting only the distinct ones).

The product of its digits is 13608, while the sum is 36.

The square root of 991173222 is about 31482.9036462649. The cubic root of 991173222 is about 997.0490410739.

The spelling of 991173222 in words is "nine hundred ninety-one million, one hundred seventy-three thousand, two hundred twenty-two".