690731 has 4 divisors (see below), whose sum is σ = 693264. Its totient is φ = 688200.

The previous prime is 690721. The next prime is 690757. The reversal of 690731 is 137096.

It is a happy number.

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 690731 - 2¹⁴ = 674347 is a prime.

It is a super-2 number, since 2×690731² = 954218628722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 690731.

It is not an unprimeable number, because it can be changed into a prime (690721) 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, 800 + ... + 1421.

It is an arithmetic number, because the mean of its divisors is an integer number (173316).

2⁶⁹⁰⁷³¹ is an apocalyptic number.

690731 is a deficient number, since it is larger than the sum of its proper divisors (2533).

690731 is a wasteful number, since it uses less digits than its factorization.

690731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2532.

The product of its (nonzero) digits is 1134, while the sum is 26.

The square root of 690731 is about 831.1022801076. The cubic root of 690731 is about 88.3967536328.

The spelling of 690731 in words is "six hundred ninety thousand, seven hundred thirty-one".