690981 has 4 divisors (see below), whose sum is σ = 921312. Its totient is φ = 460652.

The previous prime is 690953. The next prime is 690997. The reversal of 690981 is 189096.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 690981 - 2¹⁰ = 689957 is a prime.

It is a super-2 number, since 2×690981² = 954909484722, which contains 22 as substring.

It is a D-number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (690281) 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, 115161 + ... + 115166.

It is an arithmetic number, because the mean of its divisors is an integer number (230328).

2⁶⁹⁰⁹⁸¹ is an apocalyptic number.

It is an amenable number.

690981 is a deficient number, since it is larger than the sum of its proper divisors (230331).

690981 is a wasteful number, since it uses less digits than its factorization.

690981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230330.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 690981 is about 831.2526691686. The cubic root of 690981 is about 88.4074169845.

The spelling of 690981 in words is "six hundred ninety thousand, nine hundred eighty-one".