21055099 has 8 divisors (see below), whose sum is σ = 23228352. Its totient is φ = 18960960.

The previous prime is 21055087. The next prime is 21055123. The reversal of 21055099 is 99055012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21055099 - 2¹¹ = 21053051 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21055099.

It is not an unprimeable number, because it can be changed into a prime (21055399) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19219 + ... + 20284.

It is an arithmetic number, because the mean of its divisors is an integer number (2903544).

Almost surely, 2^21055099 is an apocalyptic number.

21055099 is a deficient number, since it is larger than the sum of its proper divisors (2173253).

21055099 is a wasteful number, since it uses less digits than its factorization.

21055099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39557.

The product of its (nonzero) digits is 4050, while the sum is 31.

The square root of 21055099 is about 4588.5835505088. The cubic root of 21055099 is about 276.1334989193.

The spelling of 21055099 in words is "twenty-one million, fifty-five thousand, ninety-nine".