21935549 has 2 divisors, whose sum is σ = 21935550. Its totient is φ = 21935548.

The previous prime is 21935531. The next prime is 21935581. The reversal of 21935549 is 94553912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20025625 + 1909924 = 4475^2 + 1382^2 .

It is a cyclic number.

It is not a de Polignac number, because 21935549 - 2⁸ = 21935293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21935509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10967774 + 10967775.

It is an arithmetic number, because the mean of its divisors is an integer number (10967775).

Almost surely, 2^21935549 is an apocalyptic number.

It is an amenable number.

21935549 is a deficient number, since it is larger than the sum of its proper divisors (1).

21935549 is an equidigital number, since it uses as much as digits as its factorization.

21935549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48600, while the sum is 38.

The square root of 21935549 is about 4683.5402208159. The cubic root of 21935549 is about 279.9300377925.

The spelling of 21935549 in words is "twenty-one million, nine hundred thirty-five thousand, five hundred forty-nine".