840407 has 4 divisors (see below), whose sum is σ = 858336. Its totient is φ = 822480.

The previous prime is 840353. The next prime is 840439. The reversal of 840407 is 704048.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-840407 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 840407.

It is not an unprimeable number, because it can be changed into a prime (840457) 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, 8894 + ... + 8987.

It is an arithmetic number, because the mean of its divisors is an integer number (214584).

2⁸⁴⁰⁴⁰⁷ is an apocalyptic number.

840407 is a deficient number, since it is larger than the sum of its proper divisors (17929).

840407 is a wasteful number, since it uses less digits than its factorization.

840407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17928.

The product of its (nonzero) digits is 896, while the sum is 23.

The square root of 840407 is about 916.7371488055. The cubic root of 840407 is about 94.3691160462.

The spelling of 840407 in words is "eight hundred forty thousand, four hundred seven".