21821363 has 2 divisors, whose sum is σ = 21821364. Its totient is φ = 21821362.

The previous prime is 21821351. The next prime is 21821383. The reversal of 21821363 is 36312812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21821363 - 2¹⁰ = 21820339 is a prime.

It is not a weakly prime, because it can be changed into another prime (21821333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10910681 + 10910682.

It is an arithmetic number, because the mean of its divisors is an integer number (10910682).

Almost surely, 2^21821363 is an apocalyptic number.

21821363 is a deficient number, since it is larger than the sum of its proper divisors (1).

21821363 is an equidigital number, since it uses as much as digits as its factorization.

21821363 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 26.

The square root of 21821363 is about 4671.3341777270. The cubic root of 21821363 is about 279.4434651288.

The spelling of 21821363 in words is "twenty-one million, eight hundred twenty-one thousand, three hundred sixty-three".