21790143 has 12 divisors (see below), whose sum is σ = 31515120. Its totient is φ = 14508096.

The previous prime is 21790127. The next prime is 21790157. The reversal of 21790143 is 34109712.

It is not a de Polignac number, because 21790143 - 2⁴ = 21790127 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21790123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13198 + ... + 14756.

It is an arithmetic number, because the mean of its divisors is an integer number (2626260).

Almost surely, 2^21790143 is an apocalyptic number.

21790143 is a deficient number, since it is larger than the sum of its proper divisors (9724977).

21790143 is a wasteful number, since it uses less digits than its factorization.

21790143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3118 (or 3115 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21790143 is about 4667.9913238994. The cubic root of 21790143 is about 279.3101341830.

Adding to 21790143 its reverse (34109712), we get a palindrome (55899855).

The spelling of 21790143 in words is "twenty-one million, seven hundred ninety thousand, one hundred forty-three".