21761743 has 2 divisors, whose sum is σ = 21761744. Its totient is φ = 21761742.

The previous prime is 21761731. The next prime is 21761759. The reversal of 21761743 is 34716712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21761743 - 2⁵ = 21761711 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21761723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10880871 + 10880872.

It is an arithmetic number, because the mean of its divisors is an integer number (10880872).

Almost surely, 2^21761743 is an apocalyptic number.

21761743 is a deficient number, since it is larger than the sum of its proper divisors (1).

21761743 is an equidigital number, since it uses as much as digits as its factorization.

21761743 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7056, while the sum is 31.

The square root of 21761743 is about 4664.9483384063. The cubic root of 21761743 is about 279.1887359202.

The spelling of 21761743 in words is "twenty-one million, seven hundred sixty-one thousand, seven hundred forty-three".