691281427 has 12 divisors (see below), whose sum is σ = 732516696. Its totient is φ = 652262400.

The previous prime is 691281413. The next prime is 691281433. The reversal of 691281427 is 724182196.

It is not a de Polignac number, because 691281427 - 2⁷ = 691281299 is a prime.

It is a super-2 number, since 2×691281427² = 955740022630312658, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 691281427.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691281407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 89052 + ... + 96502.

It is an arithmetic number, because the mean of its divisors is an integer number (61043058).

Almost surely, 2^691281427 is an apocalyptic number.

691281427 is a deficient number, since it is larger than the sum of its proper divisors (41235269).

691281427 is a wasteful number, since it uses less digits than its factorization.

691281427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7746 (or 7727 counting only the distinct ones).

The product of its digits is 48384, while the sum is 40.

The square root of 691281427 is about 26292.2313050833. The cubic root of 691281427 is about 884.2022781753.

The spelling of 691281427 in words is "six hundred ninety-one million, two hundred eighty-one thousand, four hundred twenty-seven".