691287484969 has 3 divisors (see below), whose sum is σ = 691288316407. Its totient is φ = 691286653532.

The previous prime is 691287484919. The next prime is 691287484973. The reversal of 691287484969 is 969484782196.

The square root of 691287484969 is 831437.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 60552905625 + 630734579344 = 246075^2 + 794188^2 .

It is not a de Polignac number, because 691287484969 - 2⁷ = 691287484841 is a prime.

It is a super-2 number, since 2×691287484969² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691287484919) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 415719 + ... + 1247155.

Almost surely, 2^691287484969 is an apocalyptic number.

691287484969 is the 831437-th square number.

691287484969 is the 415719-th centered octagonal number.

It is an amenable number.

691287484969 is a deficient number, since it is larger than the sum of its proper divisors (831438).

691287484969 is an frugal number, since it uses more digits than its factorization.

691287484969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1662874 (or 831437 counting only the distinct ones).

The product of its digits is 376233984, while the sum is 73.

The spelling of 691287484969 in words is "six hundred ninety-one billion, two hundred eighty-seven million, four hundred eighty-four thousand, nine hundred sixty-nine".