21103559 has 2 divisors, whose sum is σ = 21103560. Its totient is φ = 21103558.

The previous prime is 21103553. The next prime is 21103603. The reversal of 21103559 is 95530112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21103559 - 2¹⁶ = 21038023 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21103553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551779 + 10551780.

It is an arithmetic number, because the mean of its divisors is an integer number (10551780).

Almost surely, 2^21103559 is an apocalyptic number.

21103559 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103559 is an equidigital number, since it uses as much as digits as its factorization.

21103559 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1350, while the sum is 26.

The square root of 21103559 is about 4593.8610122641. The cubic root of 21103559 is about 276.3451844010.

The spelling of 21103559 in words is "twenty-one million, one hundred three thousand, five hundred fifty-nine".