21354943 has 2 divisors, whose sum is σ = 21354944. Its totient is φ = 21354942.

The previous prime is 21354913. The next prime is 21354959. The reversal of 21354943 is 34945312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21354943 - 2⁵ = 21354911 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21354913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10677471 + 10677472.

It is an arithmetic number, because the mean of its divisors is an integer number (10677472).

Almost surely, 2^21354943 is an apocalyptic number.

21354943 is a deficient number, since it is larger than the sum of its proper divisors (1).

21354943 is an equidigital number, since it uses as much as digits as its factorization.

21354943 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 31.

The square root of 21354943 is about 4621.1408764503. The cubic root of 21354943 is about 277.4381238011.

The spelling of 21354943 in words is "twenty-one million, three hundred fifty-four thousand, nine hundred forty-three".