21558343 has 2 divisors, whose sum is σ = 21558344. Its totient is φ = 21558342.

The previous prime is 21558319. The next prime is 21558359. The reversal of 21558343 is 34385512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21558343 - 2⁵ = 21558311 is a prime.

It is a super-4 number, since 4×21558343⁴ (a number of 30 digits) contains 4444 as substring. Note that it is a super-d number also for d = 3.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21558143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10779171 + 10779172.

It is an arithmetic number, because the mean of its divisors is an integer number (10779172).

Almost surely, 2^21558343 is an apocalyptic number.

21558343 is a deficient number, since it is larger than the sum of its proper divisors (1).

21558343 is an equidigital number, since it uses as much as digits as its factorization.

21558343 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14400, while the sum is 31.

The square root of 21558343 is about 4643.0962729627. The cubic root of 21558343 is about 278.3161827034.

The spelling of 21558343 in words is "twenty-one million, five hundred fifty-eight thousand, three hundred forty-three".