21064273 has 2 divisors, whose sum is σ = 21064274. Its totient is φ = 21064272.

The previous prime is 21064271. The next prime is 21064291. The reversal of 21064273 is 37246012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17740944 + 3323329 = 4212^2 + 1823^2 .

It is a cyclic number.

It is not a de Polignac number, because 21064273 - 2¹ = 21064271 is a prime.

Together with 21064271, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21064271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10532136 + 10532137.

It is an arithmetic number, because the mean of its divisors is an integer number (10532137).

Almost surely, 2^21064273 is an apocalyptic number.

It is an amenable number.

21064273 is a deficient number, since it is larger than the sum of its proper divisors (1).

21064273 is an equidigital number, since it uses as much as digits as its factorization.

21064273 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 21064273 is about 4589.5830965350. The cubic root of 21064273 is about 276.1735981669.

The spelling of 21064273 in words is "twenty-one million, sixty-four thousand, two hundred seventy-three".