21263263 has 8 divisors (see below), whose sum is σ = 24328832. Its totient is φ = 18204696.

The previous prime is 21263239. The next prime is 21263267. The reversal of 21263263 is 36236212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21263263 - 2⁹ = 21262751 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21263267) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10456 + ... + 12322.

It is an arithmetic number, because the mean of its divisors is an integer number (3041104).

Almost surely, 2^21263263 is an apocalyptic number.

21263263 is a deficient number, since it is larger than the sum of its proper divisors (3065569).

21263263 is a wasteful number, since it uses less digits than its factorization.

21263263 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3501.

The product of its digits is 2592, while the sum is 25.

The square root of 21263263 is about 4611.2105785791. The cubic root of 21263263 is about 277.0405263334.

Adding to 21263263 its reverse (36236212), we get a palindrome (57499475).

The spelling of 21263263 in words is "twenty-one million, two hundred sixty-three thousand, two hundred sixty-three".