21213142 has 4 divisors (see below), whose sum is σ = 31819716. Its totient is φ = 10606570.

The previous prime is 21213119. The next prime is 21213149. The reversal of 21213142 is 24131212.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5303284 + ... + 5303287.

It is an arithmetic number, because the mean of its divisors is an integer number (7954929).

Almost surely, 2^21213142 is an apocalyptic number.

21213142 is a deficient number, since it is larger than the sum of its proper divisors (10606574).

21213142 is a wasteful number, since it uses less digits than its factorization.

21213142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10606573.

The product of its digits is 96, while the sum is 16.

The square root of 21213142 is about 4605.7726821892. The cubic root of 21213142 is about 276.8226784158.

Adding to 21213142 its reverse (24131212), we get a palindrome (45344354).

The spelling of 21213142 in words is "twenty-one million, two hundred thirteen thousand, one hundred forty-two".