21253339 has 2 divisors, whose sum is σ = 21253340. Its totient is φ = 21253338.

The previous prime is 21253333. The next prime is 21253361. The reversal of 21253339 is 93335212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21253339 - 2¹⁷ = 21122267 is a prime.

It is not a weakly prime, because it can be changed into another prime (21253333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10626669 + 10626670.

It is an arithmetic number, because the mean of its divisors is an integer number (10626670).

Almost surely, 2^21253339 is an apocalyptic number.

21253339 is a deficient number, since it is larger than the sum of its proper divisors (1).

21253339 is an equidigital number, since it uses as much as digits as its factorization.

21253339 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4860, while the sum is 28.

The square root of 21253339 is about 4610.1343798202. The cubic root of 21253339 is about 276.9974194653.

The spelling of 21253339 in words is "twenty-one million, two hundred fifty-three thousand, three hundred thirty-nine".