21533542 has 4 divisors (see below), whose sum is σ = 32300316. Its totient is φ = 10766770.

The previous prime is 21533527. The next prime is 21533579. The reversal of 21533542 is 24533512.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5383384 + ... + 5383387.

It is an arithmetic number, because the mean of its divisors is an integer number (8075079).

Almost surely, 2^21533542 is an apocalyptic number.

21533542 is a deficient number, since it is larger than the sum of its proper divisors (10766774).

21533542 is a wasteful number, since it uses less digits than its factorization.

21533542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10766773.

The product of its digits is 3600, while the sum is 25.

The square root of 21533542 is about 4640.4247650404. The cubic root of 21533542 is about 278.2094155576.

The spelling of 21533542 in words is "twenty-one million, five hundred thirty-three thousand, five hundred forty-two".