840731 has 4 divisors (see below), whose sum is σ = 885000. Its totient is φ = 796464.

The previous prime is 840727. The next prime is 840733. The reversal of 840731 is 137048.

It is a happy number.

840731 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 840731 - 2² = 840727 is a prime.

It is a super-2 number, since 2×840731² = 1413657228722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 840697 and 840706.

It is not an unprimeable number, because it can be changed into a prime (840733) 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, 22106 + ... + 22143.

It is an arithmetic number, because the mean of its divisors is an integer number (221250).

2⁸⁴⁰⁷³¹ is an apocalyptic number.

840731 is a deficient number, since it is larger than the sum of its proper divisors (44269).

840731 is a wasteful number, since it uses less digits than its factorization.

840731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44268.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 840731 is about 916.9138454620. The cubic root of 840731 is about 94.3812417842.

Adding to 840731 its reverse (137048), we get a palindrome (977779).

The spelling of 840731 in words is "eight hundred forty thousand, seven hundred thirty-one".