1991992 has 32 divisors (see below), whose sum is σ = 4021920. Its totient is φ = 921600.

The previous prime is 1991989. The next prime is 1991993. The reversal of 1991992 is 2991991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13117 + ... + 13267.

It is an arithmetic number, because the mean of its divisors is an integer number (125685).

2^1991992 is an apocalyptic number.

It is an amenable number.

1991992 is an abundant number, since it is smaller than the sum of its proper divisors (2029928).

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

1991992 is a wasteful number, since it uses less digits than its factorization.

1991992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271 (or 267 counting only the distinct ones).

The product of its digits is 13122, while the sum is 40.

The square root of 1991992 is about 1411.3794670463. The cubic root of 1991992 is about 125.8237225920.

Subtracting 1991992 from its reverse (2991991), we obtain a palindrome (999999).

The spelling of 1991992 in words is "one million, nine hundred ninety-one thousand, nine hundred ninety-two".