690691 has 4 divisors (see below), whose sum is σ = 695800. Its totient is φ = 685584.

The previous prime is 690689. The next prime is 690719. The reversal of 690691 is 196096.

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

It is a 4-Lehmer number, since φ(690691) divides (690691-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 690691 - 2¹ = 690689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (690611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2346 + ... + 2623.

It is an arithmetic number, because the mean of its divisors is an integer number (173950).

2⁶⁹⁰⁶⁹¹ is an apocalyptic number.

690691 is a deficient number, since it is larger than the sum of its proper divisors (5109).

690691 is a wasteful number, since it uses less digits than its factorization.

690691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5108.

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 690691 is about 831.0782153323. The cubic root of 690691 is about 88.3950472577.

The spelling of 690691 in words is "six hundred ninety thousand, six hundred ninety-one".