691606 has 4 divisors (see below), whose sum is σ = 1037412. Its totient is φ = 345802.

The previous prime is 691591. The next prime is 691631. The reversal of 691606 is 606196.

It is a happy number.

691606 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172900 + ... + 172903.

It is an arithmetic number, because the mean of its divisors is an integer number (259353).

2⁶⁹¹⁶⁰⁶ is an apocalyptic number.

691606 is a deficient number, since it is larger than the sum of its proper divisors (345806).

691606 is a wasteful number, since it uses less digits than its factorization.

691606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345805.

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

The square root of 691606 is about 831.6285228394. The cubic root of 691606 is about 88.4340641159.

The spelling of 691606 in words is "six hundred ninety-one thousand, six hundred six".