691242938909 has 4 divisors (see below), whose sum is σ = 727624146240. Its totient is φ = 654861731580.

The previous prime is 691242938887. The next prime is 691242938917. The reversal of 691242938909 is 909839242196.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 691242938909 - 2³⁶ = 622523462173 is a prime.

It is a super-2 number, since 2×691242938909² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691242938609) 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 3 ways as a sum of consecutive naturals, for example, 18190603637 + ... + 18190603674.

It is an arithmetic number, because the mean of its divisors is an integer number (181906036560).

Almost surely, 2^691242938909 is an apocalyptic number.

It is an amenable number.

691242938909 is a deficient number, since it is larger than the sum of its proper divisors (36381207331).

691242938909 is a wasteful number, since it uses less digits than its factorization.

691242938909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36381207330.

The product of its (nonzero) digits is 15116544, while the sum is 62.

The spelling of 691242938909 in words is "six hundred ninety-one billion, two hundred forty-two million, nine hundred thirty-eight thousand, nine hundred nine".