21252143 has 8 divisors (see below), whose sum is σ = 23932416. Its totient is φ = 18696600.

The previous prime is 21252139. The next prime is 21252149. The reversal of 21252143 is 34125212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21252143 - 2² = 21252139 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21252149) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30821 + ... + 31502.

It is an arithmetic number, because the mean of its divisors is an integer number (2991552).

Almost surely, 2^21252143 is an apocalyptic number.

21252143 is a deficient number, since it is larger than the sum of its proper divisors (2680273).

21252143 is a wasteful number, since it uses less digits than its factorization.

21252143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62365.

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

The square root of 21252143 is about 4610.0046637720. The cubic root of 21252143 is about 276.9922234954.

Adding to 21252143 its reverse (34125212), we get a palindrome (55377355).

The spelling of 21252143 in words is "twenty-one million, two hundred fifty-two thousand, one hundred forty-three".