691613 has 4 divisors (see below), whose sum is σ = 744828. Its totient is φ = 638400.

The previous prime is 691591. The next prime is 691631. The reversal of 691613 is 316196.

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

It can be written as a sum of positive squares in 2 ways, for example, as 315844 + 375769 = 562^2 + 613^2 .

It is a cyclic number.

It is not a de Polignac number, because 691613 - 2¹⁰ = 690589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 691613.

It is not an unprimeable number, because it can be changed into a prime (691693) 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 in 3 ways as a sum of consecutive naturals, for example, 26588 + ... + 26613.

It is an arithmetic number, because the mean of its divisors is an integer number (186207).

2⁶⁹¹⁶¹³ is an apocalyptic number.

It is an amenable number.

691613 is a deficient number, since it is larger than the sum of its proper divisors (53215).

691613 is a wasteful number, since it uses less digits than its factorization.

691613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53214.

The product of its digits is 972, while the sum is 26.

The square root of 691613 is about 831.6327314386. The cubic root of 691613 is about 88.4343624728.

It can be divided in two parts, 6 and 91613, that added together give a palindrome (91619).

The spelling of 691613 in words is "six hundred ninety-one thousand, six hundred thirteen".