691397 has 8 divisors (see below), whose sum is σ = 808896. Its totient is φ = 578592.

The previous prime is 691381. The next prime is 691399. The reversal of 691397 is 793196.

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

It is not a de Polignac number, because 691397 - 2⁴ = 691381 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691399) 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, 848 + ... + 1449.

It is an arithmetic number, because the mean of its divisors is an integer number (101112).

2⁶⁹¹³⁹⁷ is an apocalyptic number.

It is an amenable number.

691397 is a deficient number, since it is larger than the sum of its proper divisors (117499).

691397 is a wasteful number, since it uses less digits than its factorization.

691397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2347.

The product of its digits is 10206, while the sum is 35.

The square root of 691397 is about 831.5028562789. The cubic root of 691397 is about 88.4251551024.

The spelling of 691397 in words is "six hundred ninety-one thousand, three hundred ninety-seven".