1928991 has 4 divisors (see below), whose sum is σ = 2571992. Its totient is φ = 1285992.

The previous prime is 1928989. The next prime is 1929043. The reversal of 1928991 is 1998291.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1928991 - 2¹ = 1928989 is a prime.

It is a super-3 number, since 3×1928991³ = 21533362864085238813, which contains 333 as substring.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1928951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 321496 + ... + 321501.

It is an arithmetic number, because the mean of its divisors is an integer number (642998).

2^1928991 is an apocalyptic number.

1928991 is a deficient number, since it is larger than the sum of its proper divisors (643001).

1928991 is an equidigital number, since it uses as much as digits as its factorization.

1928991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643000.

The product of its digits is 11664, while the sum is 39.

The square root of 1928991 is about 1388.8812044232. The cubic root of 1928991 is about 124.4830060190.

The spelling of 1928991 in words is "one million, nine hundred twenty-eight thousand, nine hundred ninety-one".