691326391 has 8 divisors (see below), whose sum is σ = 790331904. Its totient is φ = 592382040.

The previous prime is 691326367. The next prime is 691326413. The reversal of 691326391 is 193623196.

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 691326391 - 2⁷ = 691326263 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 (691326491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12246 + ... + 39148.

It is an arithmetic number, because the mean of its divisors is an integer number (98791488).

Almost surely, 2^691326391 is an apocalyptic number.

691326391 is a deficient number, since it is larger than the sum of its proper divisors (99005513).

691326391 is a wasteful number, since it uses less digits than its factorization.

691326391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30581.

The product of its digits is 52488, while the sum is 40.

The square root of 691326391 is about 26293.0863726570. The cubic root of 691326391 is about 884.2214485680.

The spelling of 691326391 in words is "six hundred ninety-one million, three hundred twenty-six thousand, three hundred ninety-one".