21223142 has 4 divisors (see below), whose sum is σ = 31834716. Its totient is φ = 10611570.

The previous prime is 21223141. The next prime is 21223159. The reversal of 21223142 is 24132212.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21223142.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21223141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5305784 + ... + 5305787.

It is an arithmetic number, because the mean of its divisors is an integer number (7958679).

Almost surely, 2^21223142 is an apocalyptic number.

21223142 is a deficient number, since it is larger than the sum of its proper divisors (10611574).

21223142 is a wasteful number, since it uses less digits than its factorization.

21223142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10611573.

The product of its digits is 192, while the sum is 17.

The square root of 21223142 is about 4606.8581484565. The cubic root of 21223142 is about 276.8661701957.

Adding to 21223142 its reverse (24132212), we get a palindrome (45355354).

The spelling of 21223142 in words is "twenty-one million, two hundred twenty-three thousand, one hundred forty-two".