21493542 has 32 divisors (see below), whose sum is σ = 52019712. Its totient is φ = 5779584.

The previous prime is 21493531. The next prime is 21493547. The reversal of 21493542 is 24539412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21493547) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14338 + ... + 15765.

It is an arithmetic number, because the mean of its divisors is an integer number (1625616).

Almost surely, 2^21493542 is an apocalyptic number.

21493542 is an abundant number, since it is smaller than the sum of its proper divisors (30526170).

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

21493542 is a wasteful number, since it uses less digits than its factorization.

21493542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30132.

The product of its digits is 8640, while the sum is 30.

The square root of 21493542 is about 4636.1128113971. The cubic root of 21493542 is about 278.0370445605.

The spelling of 21493542 in words is "twenty-one million, four hundred ninety-three thousand, five hundred forty-two".