21722543 has 2 divisors, whose sum is σ = 21722544. Its totient is φ = 21722542.

The previous prime is 21722531. The next prime is 21722587. The reversal of 21722543 is 34522712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21722543 - 2¹⁰ = 21721519 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21727543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10861271 + 10861272.

It is an arithmetic number, because the mean of its divisors is an integer number (10861272).

Almost surely, 2^21722543 is an apocalyptic number.

21722543 is a deficient number, since it is larger than the sum of its proper divisors (1).

21722543 is an equidigital number, since it uses as much as digits as its factorization.

21722543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3360, while the sum is 26.

The square root of 21722543 is about 4660.7448975459. The cubic root of 21722543 is about 279.0209984923.

The spelling of 21722543 in words is "twenty-one million, seven hundred twenty-two thousand, five hundred forty-three".