21776223 has 16 divisors (see below), whose sum is σ = 34929920. Its totient is φ = 11788416.

The previous prime is 21776221. The next prime is 21776233. The reversal of 21776223 is 32267712.

It is not a de Polignac number, because 21776223 - 2¹ = 21776221 is a prime.

It is the 4667-th Hogben number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21776221) by changing a digit.

It is a nontrivial repunit in base 4666.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26890 + ... + 27687.

It is an arithmetic number, because the mean of its divisors is an integer number (2183120).

Almost surely, 2^21776223 is an apocalyptic number.

21776223 is a deficient number, since it is larger than the sum of its proper divisors (13153697).

21776223 is a wasteful number, since it uses less digits than its factorization.

21776223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54606.

The product of its digits is 7056, while the sum is 30.

The square root of 21776223 is about 4666.5000803600. The cubic root of 21776223 is about 279.2506451246.

The spelling of 21776223 in words is "twenty-one million, seven hundred seventy-six thousand, two hundred twenty-three".