21883621 has 2 divisors, whose sum is σ = 21883622. Its totient is φ = 21883620.

The previous prime is 21883619. The next prime is 21883639. The reversal of 21883621 is 12638812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21622500 + 261121 = 4650^2 + 511^2 .

It is a cyclic number.

It is not a de Polignac number, because 21883621 - 2¹ = 21883619 is a prime.

Together with 21883619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21883601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10941810 + 10941811.

It is an arithmetic number, because the mean of its divisors is an integer number (10941811).

Almost surely, 2^21883621 is an apocalyptic number.

It is an amenable number.

21883621 is a deficient number, since it is larger than the sum of its proper divisors (1).

21883621 is an equidigital number, since it uses as much as digits as its factorization.

21883621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4608, while the sum is 31.

The square root of 21883621 is about 4677.9932663483. The cubic root of 21883621 is about 279.7089705707.

The spelling of 21883621 in words is "twenty-one million, eight hundred eighty-three thousand, six hundred twenty-one".