1991379 has 8 divisors (see below), whose sum is σ = 2859472. Its totient is φ = 1225440.

The previous prime is 1991359. The next prime is 1991387. The reversal of 1991379 is 9731991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1991379 - 2⁷ = 1991251 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 51061 = 1991379 / (1 + 9 + 9 + 1 + 3 + 7 + 9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1991359) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25492 + ... + 25569.

It is an arithmetic number, because the mean of its divisors is an integer number (357434).

2^1991379 is an apocalyptic number.

1991379 is a deficient number, since it is larger than the sum of its proper divisors (868093).

1991379 is a wasteful number, since it uses less digits than its factorization.

1991379 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51077.

The product of its digits is 15309, while the sum is 39.

The square root of 1991379 is about 1411.1622869110. The cubic root of 1991379 is about 125.8108145992.

The spelling of 1991379 in words is "one million, nine hundred ninety-one thousand, three hundred seventy-nine".