690581 has 4 divisors (see below), whose sum is σ = 701964. Its totient is φ = 679200.

The previous prime is 690553. The next prime is 690583. The reversal of 690581 is 185096.

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

It can be written as a sum of positive squares in 2 ways, for example, as 36100 + 654481 = 190^2 + 809^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-690581 is a prime.

It is a super-2 number, since 2×690581² = 953804235122, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (690583) 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, 5600 + ... + 5721.

It is an arithmetic number, because the mean of its divisors is an integer number (175491).

2⁶⁹⁰⁵⁸¹ is an apocalyptic number.

690581 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

690581 is a deficient number, since it is larger than the sum of its proper divisors (11383).

690581 is a wasteful number, since it uses less digits than its factorization.

690581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11382.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 690581 is about 831.0120336072. The cubic root of 690581 is about 88.3903543867.

The spelling of 690581 in words is "six hundred ninety thousand, five hundred eighty-one".