21211099 has 32 divisors (see below), whose sum is σ = 27582464. Its totient is φ = 15863040.

The previous prime is 21211079. The next prime is 21211109. The reversal of 21211099 is 99011212.

It is a cyclic number.

It is not a de Polignac number, because 21211099 - 2⁹ = 21210587 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21211009) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 205882 + ... + 205984.

It is an arithmetic number, because the mean of its divisors is an integer number (861952).

Almost surely, 2^21211099 is an apocalyptic number.

21211099 is a deficient number, since it is larger than the sum of its proper divisors (6371365).

21211099 is a wasteful number, since it uses less digits than its factorization.

21211099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227.

The product of its (nonzero) digits is 324, while the sum is 25.

The square root of 21211099 is about 4605.5508899588. The cubic root of 21211099 is about 276.8137913638.

It can be divided in two parts, 212 and 11099, that added together give a palindrome (11311).

The spelling of 21211099 in words is "twenty-one million, two hundred eleven thousand, ninety-nine".