21143252 has 18 divisors (see below), whose sum is σ = 40067118. Its totient is φ = 9758112.

The previous prime is 21143251. The next prime is 21143261. The reversal of 21143252 is 25234112.

It can be written as a sum of positive squares in 3 ways, for example, as 38416 + 21104836 = 196^2 + 4594^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21143251) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14963 + ... + 16314.

It is an arithmetic number, because the mean of its divisors is an integer number (2225951).

Almost surely, 2^21143252 is an apocalyptic number.

It is an amenable number.

21143252 is a deficient number, since it is larger than the sum of its proper divisors (18923866).

21143252 is a wasteful number, since it uses less digits than its factorization.

21143252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31307 (or 31292 counting only the distinct ones).

The product of its digits is 480, while the sum is 20.

The square root of 21143252 is about 4598.1792048592. The cubic root of 21143252 is about 276.5183321233.

Adding to 21143252 its reverse (25234112), we get a palindrome (46377364).

The spelling of 21143252 in words is "twenty-one million, one hundred forty-three thousand, two hundred fifty-two".