21059849 has 2 divisors, whose sum is σ = 21059850. Its totient is φ = 21059848.

The previous prime is 21059837. The next prime is 21059867. The reversal of 21059849 is 94895012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14684224 + 6375625 = 3832^2 + 2525^2 .

It is a cyclic number.

It is not a de Polignac number, because 21059849 - 2⁴ = 21059833 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21059879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10529924 + 10529925.

It is an arithmetic number, because the mean of its divisors is an integer number (10529925).

Almost surely, 2^21059849 is an apocalyptic number.

It is an amenable number.

21059849 is a deficient number, since it is larger than the sum of its proper divisors (1).

21059849 is an equidigital number, since it uses as much as digits as its factorization.

21059849 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 21059849 is about 4589.1011102393. The cubic root of 21059849 is about 276.1542624645.

The spelling of 21059849 in words is "twenty-one million, fifty-nine thousand, eight hundred forty-nine".