1999729 has 4 divisors (see below), whose sum is σ = 2013300. Its totient is φ = 1986160.

The previous prime is 1999721. The next prime is 1999733. The reversal of 1999729 is 9279991.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1106704 + 893025 = 1052^2 + 945^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999729 - 2³ = 1999721 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1999721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6562 + ... + 6859.

It is an arithmetic number, because the mean of its divisors is an integer number (503325).

2^1999729 is an apocalyptic number.

It is an amenable number.

1999729 is a deficient number, since it is larger than the sum of its proper divisors (13571).

1999729 is a wasteful number, since it uses less digits than its factorization.

1999729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13570.

The product of its digits is 91854, while the sum is 46.

The square root of 1999729 is about 1414.1177461584. The cubic root of 1999729 is about 125.9864140890.

The spelling of 1999729 in words is "one million, nine hundred ninety-nine thousand, seven hundred twenty-nine".