21305338 has 12 divisors (see below), whose sum is σ = 32238810. Its totient is φ = 10559736.

The previous prime is 21305321. The next prime is 21305341. The reversal of 21305338 is 83350312.

It can be written as a sum of positive squares in only one way, i.e., 20948929 + 356409 = 4577^2 + 597^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 79068 + ... + 79336.

Almost surely, 2^21305338 is an apocalyptic number.

21305338 is a deficient number, since it is larger than the sum of its proper divisors (10933472).

21305338 is an equidigital number, since it uses as much as digits as its factorization.

21305338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 669 (or 470 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 21305338 is about 4615.7705748878. The cubic root of 21305338 is about 277.2231386338.

The spelling of 21305338 in words is "twenty-one million, three hundred five thousand, three hundred thirty-eight".