690985 has 4 divisors (see below), whose sum is σ = 829188. Its totient is φ = 552784.

The previous prime is 690953. The next prime is 690997. The reversal of 690985 is 589096.

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 184041 + 506944 = 429^2 + 712^2 .

It is a cyclic number.

It is not a de Polignac number, because 690985 - 2⁵ = 690953 is a prime.

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

It is a Duffinian number.

690985 is a lucky number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69094 + ... + 69103.

It is an arithmetic number, because the mean of its divisors is an integer number (207297).

2⁶⁹⁰⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

690985 is a deficient number, since it is larger than the sum of its proper divisors (138203).

690985 is a wasteful number, since it uses less digits than its factorization.

690985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138202.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 690985 is about 831.2550751725. The cubic root of 690985 is about 88.4075875772.

The spelling of 690985 in words is "six hundred ninety thousand, nine hundred eighty-five".