21234542 has 12 divisors (see below), whose sum is σ = 37052280. Its totient is φ = 9100476.

The previous prime is 21234541. The next prime is 21234593. The reversal of 21234542 is 24543212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21234541) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 108242 + ... + 108437.

It is an arithmetic number, because the mean of its divisors is an integer number (3087690).

Almost surely, 2^21234542 is an apocalyptic number.

21234542 is a deficient number, since it is larger than the sum of its proper divisors (15817738).

21234542 is a wasteful number, since it uses less digits than its factorization.

21234542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216695 (or 216688 counting only the distinct ones).

The product of its digits is 1920, while the sum is 23.

The square root of 21234542 is about 4608.0952681124. The cubic root of 21234542 is about 276.9157341635.

Adding to 21234542 its reverse (24543212), we get a palindrome (45777754).

The spelling of 21234542 in words is "twenty-one million, two hundred thirty-four thousand, five hundred forty-two".