27721813 has 12 divisors (see below), whose sum is σ = 32066272. Its totient is φ = 23476320.

The previous prime is 27721807. The next prime is 27721829. The reversal of 27721813 is 31812772.

It is not a de Polignac number, because 27721813 - 2¹⁷ = 27590741 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27721873) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 131278 + ... + 131488.

Almost surely, 2^27721813 is an apocalyptic number.

It is an amenable number.

27721813 is a deficient number, since it is larger than the sum of its proper divisors (4344459).

27721813 is an equidigital number, since it uses as much as digits as its factorization.

27721813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492 (or 355 counting only the distinct ones).

The product of its digits is 4704, while the sum is 31.

The square root of 27721813 is about 5265.1508050577. The cubic root of 27721813 is about 302.6499058935.

The spelling of 27721813 in words is "twenty-seven million, seven hundred twenty-one thousand, eight hundred thirteen".