1979865 has 12 divisors (see below), whose sum is σ = 3431844. Its totient is φ = 1055904.

The previous prime is 1979827. The next prime is 1979891. The reversal of 1979865 is 5689791.

It can be written as a sum of positive squares in 2 ways, for example, as 589824 + 1390041 = 768^2 + 1179^2 .

It is not a de Polignac number, because 1979865 - 2⁸ = 1979609 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 43997 = 1979865 / (1 + 9 + 7 + 9 + 8 + 6 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 1979865.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 21954 + ... + 22043.

It is an arithmetic number, because the mean of its divisors is an integer number (285987).

2^1979865 is an apocalyptic number.

1979865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1979865 is a deficient number, since it is larger than the sum of its proper divisors (1451979).

1979865 is a wasteful number, since it uses less digits than its factorization.

1979865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44008 (or 44005 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The square root of 1979865 is about 1407.0767569681. The cubic root of 1979865 is about 125.5678696194.

The spelling of 1979865 in words is "one million, nine hundred seventy-nine thousand, eight hundred sixty-five".