21019277 has 2 divisors, whose sum is σ = 21019278. Its totient is φ = 21019276.

The previous prime is 21019261. The next prime is 21019279. The reversal of 21019277 is 77291012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11464996 + 9554281 = 3386^2 + 3091^2 .

It is a cyclic number.

It is not a de Polignac number, because 21019277 - 2⁴ = 21019261 is a prime.

Together with 21019279, 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 (21019279) 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, 10509638 + 10509639.

It is an arithmetic number, because the mean of its divisors is an integer number (10509639).

Almost surely, 2^21019277 is an apocalyptic number.

It is an amenable number.

21019277 is a deficient number, since it is larger than the sum of its proper divisors (1).

21019277 is an equidigital number, since it uses as much as digits as its factorization.

21019277 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1764, while the sum is 29.

The square root of 21019277 is about 4584.6785056316. The cubic root of 21019277 is about 275.9768105210.

The spelling of 21019277 in words is "twenty-one million, nineteen thousand, two hundred seventy-seven".