21942143 has 2 divisors, whose sum is σ = 21942144. Its totient is φ = 21942142.

The previous prime is 21942139. The next prime is 21942191. The reversal of 21942143 is 34124912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21942143 - 2² = 21942139 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21942113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10971071 + 10971072.

It is an arithmetic number, because the mean of its divisors is an integer number (10971072).

Almost surely, 2^21942143 is an apocalyptic number.

21942143 is a deficient number, since it is larger than the sum of its proper divisors (1).

21942143 is an equidigital number, since it uses as much as digits as its factorization.

21942143 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 26.

The square root of 21942143 is about 4684.2441225880. The cubic root of 21942143 is about 279.9580847121.

The spelling of 21942143 in words is "twenty-one million, nine hundred forty-two thousand, one hundred forty-three".