21943199 has 2 divisors, whose sum is σ = 21943200. Its totient is φ = 21943198.

The previous prime is 21943193. The next prime is 21943211. The reversal of 21943199 is 99134912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21943199 - 2¹⁶ = 21877663 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21943193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10971599 + 10971600.

It is an arithmetic number, because the mean of its divisors is an integer number (10971600).

Almost surely, 2^21943199 is an apocalyptic number.

21943199 is a deficient number, since it is larger than the sum of its proper divisors (1).

21943199 is an equidigital number, since it uses as much as digits as its factorization.

21943199 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17496, while the sum is 38.

The square root of 21943199 is about 4684.3568395245. The cubic root of 21943199 is about 279.9625757805.

The spelling of 21943199 in words is "twenty-one million, nine hundred forty-three thousand, one hundred ninety-nine".