21542384 has 20 divisors (see below), whose sum is σ = 42757680. Its totient is φ = 10508160.

The previous prime is 21542377. The next prime is 21542393. The reversal of 21542384 is 48324512.

It is a happy number.

It is a congruent number.

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, 15764 + ... + 17075.

It is an arithmetic number, because the mean of its divisors is an integer number (2137884).

Almost surely, 2^21542384 is an apocalyptic number.

It is an amenable number.

21542384 is a deficient number, since it is larger than the sum of its proper divisors (21215296).

21542384 is a wasteful number, since it uses less digits than its factorization.

21542384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32888 (or 32882 counting only the distinct ones).

The product of its digits is 7680, while the sum is 29.

The square root of 21542384 is about 4641.3773817693. The cubic root of 21542384 is about 278.2474893532.

Adding to 21542384 its reverse (48324512), we get a palindrome (69866896).

The spelling of 21542384 in words is "twenty-one million, five hundred forty-two thousand, three hundred eighty-four".