21238706 has 16 divisors (see below), whose sum is σ = 33355584. Its totient is φ = 10123344.

The previous prime is 21238687. The next prime is 21238709. The reversal of 21238706 is 60783212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21238709) 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, 17681 + ... + 18843.

It is an arithmetic number, because the mean of its divisors is an integer number (2084724).

Almost surely, 2^21238706 is an apocalyptic number.

21238706 is a deficient number, since it is larger than the sum of its proper divisors (12116878).

21238706 is a wasteful number, since it uses less digits than its factorization.

21238706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1585.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 21238706 is about 4608.5470595406. The cubic root of 21238706 is about 276.9338336317.

The spelling of 21238706 in words is "twenty-one million, two hundred thirty-eight thousand, seven hundred six".