21099563 has 2 divisors, whose sum is σ = 21099564. Its totient is φ = 21099562.

The previous prime is 21099539. The next prime is 21099587. The reversal of 21099563 is 36599012.

It is a balanced prime because it is at equal distance from previous prime (21099539) and next prime (21099587).

It is a cyclic number.

It is not a de Polignac number, because 21099563 - 2¹⁸ = 20837419 is a prime.

It is not a weakly prime, because it can be changed into another prime (21099503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10549781 + 10549782.

It is an arithmetic number, because the mean of its divisors is an integer number (10549782).

Almost surely, 2^21099563 is an apocalyptic number.

21099563 is a deficient number, since it is larger than the sum of its proper divisors (1).

21099563 is an equidigital number, since it uses as much as digits as its factorization.

21099563 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14580, while the sum is 35.

The square root of 21099563 is about 4593.4260634084. The cubic root of 21099563 is about 276.3277411337.

The spelling of 21099563 in words is "twenty-one million, ninety-nine thousand, five hundred sixty-three".