21572142 has 16 divisors (see below), whose sum is σ = 43306752. Its totient is φ = 7163640.

The previous prime is 21572141. The next prime is 21572179. The reversal of 21572142 is 24127512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21572141) 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 7 ways as a sum of consecutive naturals, for example, 5008 + ... + 8259.

It is an arithmetic number, because the mean of its divisors is an integer number (2706672).

Almost surely, 2^21572142 is an apocalyptic number.

21572142 is an abundant number, since it is smaller than the sum of its proper divisors (21734610).

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

21572142 is a wasteful number, since it uses less digits than its factorization.

21572142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13543.

The product of its digits is 1120, while the sum is 24.

The square root of 21572142 is about 4644.5820048741. The cubic root of 21572142 is about 278.3755513029.

Adding to 21572142 its reverse (24127512), we get a palindrome (45699654).

The spelling of 21572142 in words is "twenty-one million, five hundred seventy-two thousand, one hundred forty-two".