21220142 has 4 divisors (see below), whose sum is σ = 31830216. Its totient is φ = 10610070.

The previous prime is 21220109. The next prime is 21220153. The reversal of 21220142 is 24102212.

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 (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5305034 + ... + 5305037.

It is an arithmetic number, because the mean of its divisors is an integer number (7957554).

Almost surely, 2^21220142 is an apocalyptic number.

21220142 is a deficient number, since it is larger than the sum of its proper divisors (10610074).

21220142 is a wasteful number, since it uses less digits than its factorization.

21220142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10610073.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21220142 is about 4606.5325354327. The cubic root of 21220142 is about 276.8531240965.

Adding to 21220142 its reverse (24102212), we get a palindrome (45322354).

The spelling of 21220142 in words is "twenty-one million, two hundred twenty thousand, one hundred forty-two".