691385 has 8 divisors (see below), whose sum is σ = 845640. Its totient is φ = 542464.

The previous prime is 691381. The next prime is 691399. The reversal of 691385 is 583196.

691385 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 118336 + 573049 = 344^2 + 757^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 691385 - 2² = 691381 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 691385.

It is not an unprimeable number, because it can be changed into a prime (691381) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1040 + ... + 1569.

It is an arithmetic number, because the mean of its divisors is an integer number (105705).

2⁶⁹¹³⁸⁵ is an apocalyptic number.

It is an amenable number.

691385 is a deficient number, since it is larger than the sum of its proper divisors (154255).

691385 is a wasteful number, since it uses less digits than its factorization.

691385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2667.

The product of its digits is 6480, while the sum is 32.

The square root of 691385 is about 831.4956403975. The cubic root of 691385 is about 88.4246435256.

The spelling of 691385 in words is "six hundred ninety-one thousand, three hundred eighty-five".