1981979 has 16 divisors (see below), whose sum is σ = 2265408. Its totient is φ = 1723392.

The previous prime is 1981963. The next prime is 1981997. The reversal of 1981979 is 9791891.

It is not a de Polignac number, because 1981979 - 2⁴ = 1981963 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1981919) 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 15 ways as a sum of consecutive naturals, for example, 14399 + ... + 14535.

It is an arithmetic number, because the mean of its divisors is an integer number (141588).

2^1981979 is an apocalyptic number.

1981979 is a deficient number, since it is larger than the sum of its proper divisors (283429).

1981979 is a wasteful number, since it uses less digits than its factorization.

1981979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214.

The product of its digits is 40824, while the sum is 44.

The square root of 1981979 is about 1407.8277593513. The cubic root of 1981979 is about 125.6125454019.

The spelling of 1981979 in words is "one million, nine hundred eighty-one thousand, nine hundred seventy-nine".