21775105 has 16 divisors (see below), whose sum is σ = 28597824. Its totient is φ = 15785280.

The previous prime is 21775099. The next prime is 21775123. The reversal of 21775105 is 50157712.

It is not a de Polignac number, because 21775105 - 2¹⁷ = 21644033 is a prime.

It is a super-2 number, since 2×21775105² = 948310395522050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28387 + ... + 29143.

It is an arithmetic number, because the mean of its divisors is an integer number (1787364).

Almost surely, 2^21775105 is an apocalyptic number.

It is an amenable number.

21775105 is a deficient number, since it is larger than the sum of its proper divisors (6822719).

21775105 is a wasteful number, since it uses less digits than its factorization.

21775105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1296.

The product of its (nonzero) digits is 2450, while the sum is 28.

The square root of 21775105 is about 4666.3802888320. The cubic root of 21775105 is about 279.2458660962.

The spelling of 21775105 in words is "twenty-one million, seven hundred seventy-five thousand, one hundred five".