21764143 has 2 divisors, whose sum is σ = 21764144. Its totient is φ = 21764142.

The previous prime is 21764137. The next prime is 21764179. The reversal of 21764143 is 34146712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21764143 - 2⁵ = 21764111 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21764543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10882071 + 10882072.

It is an arithmetic number, because the mean of its divisors is an integer number (10882072).

Almost surely, 2^21764143 is an apocalyptic number.

21764143 is a deficient number, since it is larger than the sum of its proper divisors (1).

21764143 is an equidigital number, since it uses as much as digits as its factorization.

21764143 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 28.

The square root of 21764143 is about 4665.2055688898. The cubic root of 21764143 is about 279.1989990126.

The spelling of 21764143 in words is "twenty-one million, seven hundred sixty-four thousand, one hundred forty-three".