21406263 has 8 divisors (see below), whose sum is σ = 29526000. Its totient is φ = 13778688.

The previous prime is 21406249. The next prime is 21406271. The reversal of 21406263 is 36260412.

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

It is not a de Polignac number, because 21406263 - 2⁶ = 21406199 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21406163) 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, 122938 + ... + 123111.

It is an arithmetic number, because the mean of its divisors is an integer number (3690750).

Almost surely, 2^21406263 is an apocalyptic number.

21406263 is a deficient number, since it is larger than the sum of its proper divisors (8119737).

21406263 is a wasteful number, since it uses less digits than its factorization.

21406263 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246081.

The product of its (nonzero) digits is 1728, while the sum is 24.

The square root of 21406263 is about 4626.6902857226. The cubic root of 21406263 is about 277.6601915768.

Adding to 21406263 its reverse (36260412), we get a palindrome (57666675).

The spelling of 21406263 in words is "twenty-one million, four hundred six thousand, two hundred sixty-three".