690645 has 16 divisors (see below), whose sum is σ = 1132992. Its totient is φ = 359040.

The previous prime is 690629. The next prime is 690661. The reversal of 690645 is 546096.

690645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (690629) and next prime (690661).

It is not a de Polignac number, because 690645 - 2⁴ = 690629 is a prime.

It is an Ulam number.

It is a Curzon number.

It is a nialpdrome in base 15.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54 + ... + 1176.

It is an arithmetic number, because the mean of its divisors is an integer number (70812).

2⁶⁹⁰⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

690645 is a deficient number, since it is larger than the sum of its proper divisors (442347).

690645 is a wasteful number, since it uses less digits than its factorization.

690645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1172.

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 690645 is about 831.0505399794. The cubic root of 690645 is about 88.3930848450.

The spelling of 690645 in words is "six hundred ninety thousand, six hundred forty-five".