21236734 has 4 divisors (see below), whose sum is σ = 31855104. Its totient is φ = 10618366.

The previous prime is 21236731. The next prime is 21236749. The reversal of 21236734 is 43763212.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21236731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5309182 + ... + 5309185.

It is an arithmetic number, because the mean of its divisors is an integer number (7963776).

Almost surely, 2^21236734 is an apocalyptic number.

21236734 is a deficient number, since it is larger than the sum of its proper divisors (10618370).

21236734 is a wasteful number, since it uses less digits than its factorization.

21236734 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10618369.

The product of its digits is 6048, while the sum is 28.

The square root of 21236734 is about 4608.3331042797. Note that the first 3 decimals coincide. The cubic root of 21236734 is about 276.9252623245.

Adding to 21236734 its reverse (43763212), we get a palindrome (64999946).

The spelling of 21236734 in words is "twenty-one million, two hundred thirty-six thousand, seven hundred thirty-four".