27691821 has 8 divisors (see below), whose sum is σ = 41024960. Its totient is φ = 18461196.

The previous prime is 27691819. The next prime is 27691831. The reversal of 27691821 is 12819672.

It is not a de Polignac number, because 27691821 - 2¹ = 27691819 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 (27691801) 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 7 ways as a sum of consecutive naturals, for example, 512785 + ... + 512838.

It is an arithmetic number, because the mean of its divisors is an integer number (5128120).

Almost surely, 2^27691821 is an apocalyptic number.

It is an amenable number.

27691821 is a deficient number, since it is larger than the sum of its proper divisors (13333139).

27691821 is a wasteful number, since it uses less digits than its factorization.

27691821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1025632 (or 1025626 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 27691821 is about 5262.3018727549. The cubic root of 27691821 is about 302.5407216996.

The spelling of 27691821 in words is "twenty-seven million, six hundred ninety-one thousand, eight hundred twenty-one".