690639 has 4 divisors (see below), whose sum is σ = 920856. Its totient is φ = 460424.

The previous prime is 690629. The next prime is 690661. The reversal of 690639 is 936096.

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 690639 - 2⁵ = 690607 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (690629) 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, 115104 + ... + 115109.

It is an arithmetic number, because the mean of its divisors is an integer number (230214).

2⁶⁹⁰⁶³⁹ is an apocalyptic number.

690639 is a deficient number, since it is larger than the sum of its proper divisors (230217).

690639 is a wasteful number, since it uses less digits than its factorization.

690639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230216.

The product of its (nonzero) digits is 8748, while the sum is 33.

The square root of 690639 is about 831.0469300828. The cubic root of 690639 is about 88.3928288717.

The spelling of 690639 in words is "six hundred ninety thousand, six hundred thirty-nine".