1999679 has 4 divisors (see below), whose sum is σ = 2181480. Its totient is φ = 1817880.

The previous prime is 1999667. The next prime is 1999681. The reversal of 1999679 is 9769991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1999679 - 2⁸ = 1999423 is a prime.

It is a super-2 number, since 2×1999679² = 7997432206082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1999619) 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, 90884 + ... + 90905.

It is an arithmetic number, because the mean of its divisors is an integer number (545370).

2^1999679 is an apocalyptic number.

1999679 is a deficient number, since it is larger than the sum of its proper divisors (181801).

1999679 is a wasteful number, since it uses less digits than its factorization.

1999679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181800.

The product of its digits is 275562, while the sum is 50.

The square root of 1999679 is about 1414.1000671805. The cubic root of 1999679 is about 125.9853640512.

The spelling of 1999679 in words is "one million, nine hundred ninety-nine thousand, six hundred seventy-nine".