21142472 has 16 divisors (see below), whose sum is σ = 42691740. Its totient is φ = 9758016.

The previous prime is 21142469. The next prime is 21142477. The reversal of 21142472 is 27424112.

It can be written as a sum of positive squares in 2 ways, for example, as 21104836 + 37636 = 4594^2 + 194^2 .

It is not an unprimeable number, because it can be changed into a prime (21142477) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 101543 + ... + 101750.

Almost surely, 2^21142472 is an apocalyptic number.

It is an amenable number.

21142472 is an abundant number, since it is smaller than the sum of its proper divisors (21549268).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21142472 is a wasteful number, since it uses less digits than its factorization.

21142472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203312 (or 203308 counting only the distinct ones).

The product of its digits is 896, while the sum is 23.

The square root of 21142472 is about 4598.0943878959. The cubic root of 21142472 is about 276.5149317169.

Adding to 21142472 its reverse (27424112), we get a palindrome (48566584).

The spelling of 21142472 in words is "twenty-one million, one hundred forty-two thousand, four hundred seventy-two".