840729 has 4 divisors (see below), whose sum is σ = 1120976. Its totient is φ = 560484.

The previous prime is 840727. The next prime is 840733. The reversal of 840729 is 927048.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 840729 - 2¹ = 840727 is a prime.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 840696 and 840705.

It is not an unprimeable number, because it can be changed into a prime (840727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 140119 + ... + 140124.

It is an arithmetic number, because the mean of its divisors is an integer number (280244).

2⁸⁴⁰⁷²⁹ is an apocalyptic number.

It is an amenable number.

840729 is a deficient number, since it is larger than the sum of its proper divisors (280247).

840729 is a wasteful number, since it uses less digits than its factorization.

840729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280246.

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 840729 is about 916.9127548464. The cubic root of 840729 is about 94.3811669435.

The spelling of 840729 in words is "eight hundred forty thousand, seven hundred twenty-nine".