27957821 has 2 divisors, whose sum is σ = 27957822.
Its totient is φ = 27957820.
The previous prime is 27957791. The next prime is 27957823. The reversal of 27957821 is 12875972.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 22221796 + 5736025 = 4714^2 + 2395^2
It is a cyclic number.
It is not a de Polignac number, because 27957821 - 222 = 23763517 is a prime.
Together with 27957823, it forms a pair of twin primes.
It is a Chen prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (27957823) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13978910 + 13978911.
It is an arithmetic number, because the mean of its divisors is an integer number (13978911).
Almost surely, 227957821 is an apocalyptic number.
It is an amenable number.
27957821 is a deficient number, since it is larger than the sum of its proper divisors (1).
27957821 is an equidigital number, since it uses as much as digits as its factorization.
27957821 is an evil number, because the sum of its binary digits is even.
The product of its digits is 70560, while the sum is 41.
The square root of 27957821 is about 5287.5155791733.
The cubic root of 27957821 is about 303.5063440290.
The spelling of 27957821 in words is "twenty-seven million, nine hundred fifty-seven thousand, eight hundred twenty-one".