21943351 has 2 divisors, whose sum is σ = 21943352. Its totient is φ = 21943350.

The previous prime is 21943333. The next prime is 21943387. The reversal of 21943351 is 15334912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21943351 - 2⁹ = 21942839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21943301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10971675 + 10971676.

It is an arithmetic number, because the mean of its divisors is an integer number (10971676).

Almost surely, 2^21943351 is an apocalyptic number.

21943351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21943351 is an equidigital number, since it uses as much as digits as its factorization.

21943351 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 28.

The square root of 21943351 is about 4684.3730637087. The cubic root of 21943351 is about 279.9632222103.

The spelling of 21943351 in words is "twenty-one million, nine hundred forty-three thousand, three hundred fifty-one".