20421143 has 8 divisors (see below), whose sum is σ = 21544320. Its totient is φ = 19302840.

The previous prime is 20421103. The next prime is 20421179. The reversal of 20421143 is 34112402.

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 20421143 - 2¹⁰ = 20420119 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421103) 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, 10238 + ... + 12068.

It is an arithmetic number, because the mean of its divisors is an integer number (2693040).

Almost surely, 2^20421143 is an apocalyptic number.

20421143 is a deficient number, since it is larger than the sum of its proper divisors (1123177).

20421143 is a wasteful number, since it uses less digits than its factorization.

20421143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2437.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 20421143 is about 4518.9758795550. The cubic root of 20421143 is about 273.3338061000. Note that the first 3 decimals are identical.

Adding to 20421143 its reverse (34112402), we get a palindrome (54533545).

The spelling of 20421143 in words is "twenty million, four hundred twenty-one thousand, one hundred forty-three".