21250143 has 12 divisors (see below), whose sum is σ = 31198648. Its totient is φ = 13934160.

The previous prime is 21250139. The next prime is 21250171. The reversal of 21250143 is 34105212.

It is not a de Polignac number, because 21250143 - 2² = 21250139 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 (21250123) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18805 + ... + 19902.

Almost surely, 2^21250143 is an apocalyptic number.

21250143 is a deficient number, since it is larger than the sum of its proper divisors (9948505).

21250143 is a wasteful number, since it uses less digits than its factorization.

21250143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38774 (or 38771 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21250143 is about 4609.7877391481. The cubic root of 21250143 is about 276.9835341470.

Adding to 21250143 its reverse (34105212), we get a palindrome (55355355).

The spelling of 21250143 in words is "twenty-one million, two hundred fifty thousand, one hundred forty-three".