840669 has 4 divisors (see below), whose sum is σ = 1120896. Its totient is φ = 560444.

The previous prime is 840661. The next prime is 840683. The reversal of 840669 is 966048.

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 a cyclic number.

It is not a de Polignac number, because 840669 - 2³ = 840661 is a prime.

It is a super-2 number, since 2×840669² = 1413448735122, which contains 22 as substring.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840661) 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, 140109 + ... + 140114.

It is an arithmetic number, because the mean of its divisors is an integer number (280224).

2⁸⁴⁰⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

840669 is a deficient number, since it is larger than the sum of its proper divisors (280227).

840669 is a wasteful number, since it uses less digits than its factorization.

840669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280226.

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 840669 is about 916.8800357735. The cubic root of 840669 is about 94.3789216680.

The spelling of 840669 in words is "eight hundred forty thousand, six hundred sixty-nine".