21055277 has 2 divisors, whose sum is σ = 21055278. Its totient is φ = 21055276.

The previous prime is 21055261. The next prime is 21055291. The reversal of 21055277 is 77255012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13498276 + 7557001 = 3674^2 + 2749^2 .

It is a cyclic number.

It is not a de Polignac number, because 21055277 - 2⁴ = 21055261 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21055207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10527638 + 10527639.

It is an arithmetic number, because the mean of its divisors is an integer number (10527639).

Almost surely, 2^21055277 is an apocalyptic number.

It is an amenable number.

21055277 is a deficient number, since it is larger than the sum of its proper divisors (1).

21055277 is an equidigital number, since it uses as much as digits as its factorization.

21055277 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4900, while the sum is 29.

The square root of 21055277 is about 4588.6029464315. The cubic root of 21055277 is about 276.1342770622.

The spelling of 21055277 in words is "twenty-one million, fifty-five thousand, two hundred seventy-seven".