21542242 has 16 divisors (see below), whose sum is σ = 32959872. Its totient is φ = 10557360.

The previous prime is 21542233. The next prime is 21542263. The reversal of 21542242 is 24224512.

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 in 7 ways as a sum of consecutive naturals, for example, 49767 + ... + 50197.

It is an arithmetic number, because the mean of its divisors is an integer number (2059992).

Almost surely, 2^21542242 is an apocalyptic number.

21542242 is a deficient number, since it is larger than the sum of its proper divisors (11417630).

21542242 is a wasteful number, since it uses less digits than its factorization.

21542242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 873.

The product of its digits is 1280, while the sum is 22.

The square root of 21542242 is about 4641.3620845610. The cubic root of 21542242 is about 278.2468779812.

Adding to 21542242 its reverse (24224512), we get a palindrome (45766754).

The spelling of 21542242 in words is "twenty-one million, five hundred forty-two thousand, two hundred forty-two".