690945 has 16 divisors (see below), whose sum is σ = 1122432. Its totient is φ = 362880.

The previous prime is 690929. The next prime is 690953. The reversal of 690945 is 549096.

It is a happy number.

It is not a de Polignac number, because 690945 - 2⁴ = 690929 is a prime.

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

690945 is a lucky number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 780 + ... + 1410.

It is an arithmetic number, because the mean of its divisors is an integer number (70152).

2⁶⁹⁰⁹⁴⁵ is an apocalyptic number.

It is an amenable number.

690945 is a deficient number, since it is larger than the sum of its proper divisors (431487).

690945 is a wasteful number, since it uses less digits than its factorization.

690945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 712.

The product of its (nonzero) digits is 9720, while the sum is 33.

The square root of 690945 is about 831.2310148208. The cubic root of 690945 is about 88.4058816204.

It can be divided in two parts, 6 and 90945, that added together give a triangular number (90951 = T₄₂₆).

The spelling of 690945 in words is "six hundred ninety thousand, nine hundred forty-five".