27731511221 has 2 divisors, whose sum is σ = 27731511222. Its totient is φ = 27731511220.

The previous prime is 27731511209. The next prime is 27731511253. The reversal of 27731511221 is 12211513772.

It is an a-pointer prime, because the next prime (27731511253) can be obtained adding 27731511221 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16271808721 + 11459702500 = 127561^2 + 107050^2 .

It is a cyclic number.

It is not a de Polignac number, because 27731511221 - 2²⁶ = 27664402357 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27731511271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13865755610 + 13865755611.

It is an arithmetic number, because the mean of its divisors is an integer number (13865755611).

Almost surely, 2^27731511221 is an apocalyptic number.

It is an amenable number.

27731511221 is a deficient number, since it is larger than the sum of its proper divisors (1).

27731511221 is an equidigital number, since it uses as much as digits as its factorization.

27731511221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5880, while the sum is 32.

The spelling of 27731511221 in words is "twenty-seven billion, seven hundred thirty-one million, five hundred eleven thousand, two hundred twenty-one".