1991330 has 32 divisors (see below), whose sum is σ = 4010688. Its totient is φ = 705600.

The previous prime is 1991293. The next prime is 1991351. The reversal of 1991330 is 331991.

It is a self number, because there is not a number n which added to its sum of digits gives 1991330.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4520 + ... + 4940.

It is an arithmetic number, because the mean of its divisors is an integer number (125334).

2^1991330 is an apocalyptic number.

1991330 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1991330 is an abundant number, since it is smaller than the sum of its proper divisors (2019358).

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

1991330 is a wasteful number, since it uses less digits than its factorization.

1991330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 482.

The product of its (nonzero) digits is 729, while the sum is 26.

The square root of 1991330 is about 1411.1449252292. The cubic root of 1991330 is about 125.8097826877.

The spelling of 1991330 in words is "one million, nine hundred ninety-one thousand, three hundred thirty".