1991469 has 4 divisors (see below), whose sum is σ = 2655296. Its totient is φ = 1327644.

The previous prime is 1991461. The next prime is 1991477. The reversal of 1991469 is 9641991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (1991461) and next prime (1991477).

It is not a de Polignac number, because 1991469 - 2³ = 1991461 is a prime.

It is a super-2 number, since 2×1991469² = 7931897555922, which contains 22 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 (1991461) 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, 331909 + ... + 331914.

It is an arithmetic number, because the mean of its divisors is an integer number (663824).

2^1991469 is an apocalyptic number.

It is an amenable number.

1991469 is a deficient number, since it is larger than the sum of its proper divisors (663827).

1991469 is an equidigital number, since it uses as much as digits as its factorization.

1991469 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663826.

The product of its digits is 17496, while the sum is 39.

The square root of 1991469 is about 1411.1941751580. The cubic root of 1991469 is about 125.8127099027.

The spelling of 1991469 in words is "one million, nine hundred ninety-one thousand, four hundred sixty-nine".