21255077 has 2 divisors, whose sum is σ = 21255078. Its totient is φ = 21255076.

The previous prime is 21255061. The next prime is 21255079. The reversal of 21255077 is 77055212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20784481 + 470596 = 4559^2 + 686^2 .

It is a cyclic number.

It is not a de Polignac number, because 21255077 - 2⁴ = 21255061 is a prime.

Together with 21255079, 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 (21255079) 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, 10627538 + 10627539.

It is an arithmetic number, because the mean of its divisors is an integer number (10627539).

Almost surely, 2^21255077 is an apocalyptic number.

It is an amenable number.

21255077 is a deficient number, since it is larger than the sum of its proper divisors (1).

21255077 is an equidigital number, since it uses as much as digits as its factorization.

21255077 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 21255077 is about 4610.3228737259. The cubic root of 21255077 is about 277.0049697832.

The spelling of 21255077 in words is "twenty-one million, two hundred fifty-five thousand, seventy-seven".