1991673 has 12 divisors (see below), whose sum is σ = 2955108. Its totient is φ = 1291680.

The previous prime is 1991653. The next prime is 1991677. The reversal of 1991673 is 3761991.

It can be written as a sum of positive squares in 2 ways, for example, as 831744 + 1159929 = 912^2 + 1077^2 .

It is not a de Polignac number, because 1991673 - 2⁵ = 1991641 is a prime.

It is a super-2 number, since 2×1991673² = 7933522677858, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (1991677) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2658 + ... + 3323.

It is an arithmetic number, because the mean of its divisors is an integer number (246259).

2^1991673 is an apocalyptic number.

It is an amenable number.

1991673 is a deficient number, since it is larger than the sum of its proper divisors (963435).

1991673 is a wasteful number, since it uses less digits than its factorization.

1991673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6024 (or 6021 counting only the distinct ones).

The product of its digits is 10206, while the sum is 36.

The square root of 1991673 is about 1411.2664525170. The cubic root of 1991673 is about 125.8170057125.

The spelling of 1991673 in words is "one million, nine hundred ninety-one thousand, six hundred seventy-three".