21236234 has 4 divisors (see below), whose sum is σ = 31854354. Its totient is φ = 10618116.

The previous prime is 21236219. The next prime is 21236239. The reversal of 21236234 is 43263212.

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

It can be written as a sum of positive squares in only one way, i.e., 15960025 + 5276209 = 3995^2 + 2297^2 .

It is not an unprimeable number, because it can be changed into a prime (21236239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5309057 + ... + 5309060.

Almost surely, 2^21236234 is an apocalyptic number.

21236234 is a deficient number, since it is larger than the sum of its proper divisors (10618120).

21236234 is a wasteful number, since it uses less digits than its factorization.

21236234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10618119.

The product of its digits is 1728, while the sum is 23.

The square root of 21236234 is about 4608.2788544097. The cubic root of 21236234 is about 276.9230889878.

Adding to 21236234 its reverse (43263212), we get a palindrome (64499446).

The spelling of 21236234 in words is "twenty-one million, two hundred thirty-six thousand, two hundred thirty-four".