1391979 has 4 divisors (see below), whose sum is σ = 1855976. Its totient is φ = 927984.

The previous prime is 1391969. The next prime is 1391981. The reversal of 1391979 is 9791931.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9791931 = 3 ⋅3263977.

It is not a de Polignac number, because 1391979 - 2¹⁶ = 1326443 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1391969) by changing a digit.

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, 231994 + ... + 231999.

It is an arithmetic number, because the mean of its divisors is an integer number (463994).

2^1391979 is an apocalyptic number.

1391979 is a deficient number, since it is larger than the sum of its proper divisors (463997).

1391979 is an equidigital number, since it uses as much as digits as its factorization.

1391979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 463996.

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

The square root of 1391979 is about 1179.8215966832. The cubic root of 1391979 is about 111.6548419448.

The spelling of 1391979 in words is "one million, three hundred ninety-one thousand, nine hundred seventy-nine".