21943793 has 2 divisors, whose sum is σ = 21943794. Its totient is φ = 21943792.

The previous prime is 21943781. The next prime is 21943813. The reversal of 21943793 is 39734912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21603904 + 339889 = 4648^2 + 583^2 .

It is a cyclic number.

It is not a de Polignac number, because 21943793 - 2⁶ = 21943729 is a prime.

It is equal to p_1385948 and since 21943793 and 1385948 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21943703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10971896 + 10971897.

It is an arithmetic number, because the mean of its divisors is an integer number (10971897).

Almost surely, 2^21943793 is an apocalyptic number.

It is an amenable number.

21943793 is a deficient number, since it is larger than the sum of its proper divisors (1).

21943793 is an equidigital number, since it uses as much as digits as its factorization.

21943793 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40824, while the sum is 38.

The square root of 21943793 is about 4684.4202416094. The cubic root of 21943793 is about 279.9651019431.

The spelling of 21943793 in words is "twenty-one million, nine hundred forty-three thousand, seven hundred ninety-three".