27831821 has 2 divisors, whose sum is σ = 27831822. Its totient is φ = 27831820.

The previous prime is 27831781. The next prime is 27831823. The reversal of 27831821 is 12813872.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23629321 + 4202500 = 4861^2 + 2050^2 .

It is a cyclic number.

It is not a de Polignac number, because 27831821 - 2¹⁰ = 27830797 is a prime.

It is a super-2 number, since 2×27831821² = 1549220520352082, which contains 22 as substring.

Together with 27831823, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_1731596 and since 27831821 and 1731596 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27831823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13915910 + 13915911.

It is an arithmetic number, because the mean of its divisors is an integer number (13915911).

Almost surely, 2^27831821 is an apocalyptic number.

It is an amenable number.

27831821 is a deficient number, since it is larger than the sum of its proper divisors (1).

27831821 is an equidigital number, since it uses as much as digits as its factorization.

27831821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5376, while the sum is 32.

The square root of 27831821 is about 5275.5872658880. The cubic root of 27831821 is about 303.0497110072.

The spelling of 27831821 in words is "twenty-seven million, eight hundred thirty-one thousand, eight hundred twenty-one".