1915989 has 4 divisors (see below), whose sum is σ = 2554656. Its totient is φ = 1277324.

The previous prime is 1915981. The next prime is 1915993. The reversal of 1915989 is 9895191.

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 a cyclic number.

It is not a de Polignac number, because 1915989 - 2³ = 1915981 is a prime.

It is a D-number.

1915989 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1915989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1915981) 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, 319329 + ... + 319334.

It is an arithmetic number, because the mean of its divisors is an integer number (638664).

2^1915989 is an apocalyptic number.

It is an amenable number.

1915989 is a deficient number, since it is larger than the sum of its proper divisors (638667).

1915989 is an equidigital number, since it uses as much as digits as its factorization.

1915989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638666.

The product of its digits is 29160, while the sum is 42.

The square root of 1915989 is about 1384.1925444099. The cubic root of 1915989 is about 124.2026905270.

The spelling of 1915989 in words is "one million, nine hundred fifteen thousand, nine hundred eighty-nine".