21234756 has 12 divisors (see below), whose sum is σ = 49547792. Its totient is φ = 7078248.

The previous prime is 21234713. The next prime is 21234767. The reversal of 21234756 is 65743212.

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 884770 + ... + 884793.

Almost surely, 2^21234756 is an apocalyptic number.

It is an amenable number.

21234756 is an abundant number, since it is smaller than the sum of its proper divisors (28313036).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21234756 is a wasteful number, since it uses less digits than its factorization.

21234756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1769570 (or 1769568 counting only the distinct ones).

The product of its digits is 10080, while the sum is 30.

The square root of 21234756 is about 4608.1184880600. The cubic root of 21234756 is about 276.9166644052.

Adding to 21234756 its reverse (65743212), we get a palindrome (86977968).

The spelling of 21234756 in words is "twenty-one million, two hundred thirty-four thousand, seven hundred fifty-six".