20280143 has 4 divisors (see below), whose sum is σ = 21840168. Its totient is φ = 18720120.

The previous prime is 20280119. The next prime is 20280149. The reversal of 20280143 is 34108202.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20280143 is a prime.

It is a super-2 number, since 2×20280143² = 822568400200898, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20280149) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 779993 + ... + 780018.

It is an arithmetic number, because the mean of its divisors is an integer number (5460042).

Almost surely, 2^20280143 is an apocalyptic number.

20280143 is a deficient number, since it is larger than the sum of its proper divisors (1560025).

20280143 is a wasteful number, since it uses less digits than its factorization.

20280143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1560024.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 20280143 is about 4503.3479767835. The cubic root of 20280143 is about 272.7032650012.

Adding to 20280143 its reverse (34108202), we get a palindrome (54388345).

The spelling of 20280143 in words is "twenty million, two hundred eighty thousand, one hundred forty-three".