1991420 has 12 divisors (see below), whose sum is σ = 4182024. Its totient is φ = 796560.

The previous prime is 1991413. The next prime is 1991443. The reversal of 1991420 is 241991.

It is a self number, because there is not a number n which added to its sum of digits gives 1991420.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49766 + ... + 49805.

It is an arithmetic number, because the mean of its divisors is an integer number (348502).

2^1991420 is an apocalyptic number.

1991420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1991420 is an abundant number, since it is smaller than the sum of its proper divisors (2190604).

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

1991420 is a wasteful number, since it uses less digits than its factorization.

1991420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99580 (or 99578 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 1991420 is about 1411.1768138685. The cubic root of 1991420 is about 125.8116780223.

The spelling of 1991420 in words is "one million, nine hundred ninety-one thousand, four hundred twenty".