21263339 has 4 divisors (see below), whose sum is σ = 22187856. Its totient is φ = 20338824.

The previous prime is 21263309. The next prime is 21263353. The reversal of 21263339 is 93336212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21263339 - 2⁸ = 21263083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21263309) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 462224 + ... + 462269.

It is an arithmetic number, because the mean of its divisors is an integer number (5546964).

Almost surely, 2^21263339 is an apocalyptic number.

21263339 is a deficient number, since it is larger than the sum of its proper divisors (924517).

21263339 is an equidigital number, since it uses as much as digits as its factorization.

21263339 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 924516.

The product of its digits is 5832, while the sum is 29.

The square root of 21263339 is about 4611.2188193578. The cubic root of 21263339 is about 277.0408564028.

The spelling of 21263339 in words is "twenty-one million, two hundred sixty-three thousand, three hundred thirty-nine".