691066 has 4 divisors (see below), whose sum is σ = 1036602. Its totient is φ = 345532.

The previous prime is 691063. The next prime is 691079. The reversal of 691066 is 660196.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 469225 + 221841 = 685^2 + 471^2 .

It is not an unprimeable number, because it can be changed into a prime (691063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172765 + ... + 172768.

2⁶⁹¹⁰⁶⁶ is an apocalyptic number.

691066 is a deficient number, since it is larger than the sum of its proper divisors (345536).

691066 is a wasteful number, since it uses less digits than its factorization.

691066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345535.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 691066 is about 831.3037952518. The cubic root of 691066 is about 88.4110419381.

The spelling of 691066 in words is "six hundred ninety-one thousand, sixty-six".