21236534 has 16 divisors (see below), whose sum is σ = 34845120. Its totient is φ = 9626760.

The previous prime is 21236491. The next prime is 21236561. The reversal of 21236534 is 43563212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8657 + ... + 10835.

It is an arithmetic number, because the mean of its divisors is an integer number (2177820).

Almost surely, 2^21236534 is an apocalyptic number.

21236534 is a deficient number, since it is larger than the sum of its proper divisors (13608586).

21236534 is a wasteful number, since it uses less digits than its factorization.

21236534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2635.

The product of its digits is 4320, while the sum is 26.

The square root of 21236534 is about 4608.3114044083. The cubic root of 21236534 is about 276.9243929939.

Adding to 21236534 its reverse (43563212), we get a palindrome (64799746).

The spelling of 21236534 in words is "twenty-one million, two hundred thirty-six thousand, five hundred thirty-four".