21422542 has 4 divisors (see below), whose sum is σ = 32133816. Its totient is φ = 10711270.

The previous prime is 21422537. The next prime is 21422551. The reversal of 21422542 is 24522412.

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

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5355634 + ... + 5355637.

It is an arithmetic number, because the mean of its divisors is an integer number (8033454).

Almost surely, 2^21422542 is an apocalyptic number.

21422542 is a deficient number, since it is larger than the sum of its proper divisors (10711274).

21422542 is a wasteful number, since it uses less digits than its factorization.

21422542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10711273.

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

The square root of 21422542 is about 4628.4492003262. The cubic root of 21422542 is about 277.7305585989.

Adding to 21422542 its reverse (24522412), we get a palindrome (45944954).

The spelling of 21422542 in words is "twenty-one million, four hundred twenty-two thousand, five hundred forty-two".