690681 has 4 divisors (see below), whose sum is σ = 920912. Its totient is φ = 460452.

The previous prime is 690673. The next prime is 690689. The reversal of 690681 is 186096.

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 an interprime number because it is at equal distance from previous prime (690673) and next prime (690689).

It is not a de Polignac number, because 690681 - 2³ = 690673 is a prime.

It is a super-2 number, since 2×690681² = 954080487522, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (690689) 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, 115111 + ... + 115116.

It is an arithmetic number, because the mean of its divisors is an integer number (230228).

2⁶⁹⁰⁶⁸¹ is an apocalyptic number.

It is an amenable number.

690681 is a deficient number, since it is larger than the sum of its proper divisors (230231).

690681 is a wasteful number, since it uses less digits than its factorization.

690681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230230.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 690681 is about 831.0721990297. The cubic root of 690681 is about 88.3946206537.

The spelling of 690681 in words is "six hundred ninety thousand, six hundred eighty-one".