21776161 has 8 divisors (see below), whose sum is σ = 23794848. Its totient is φ = 19764000.

The previous prime is 21776149. The next prime is 21776213. The reversal of 21776161 is 16167712.

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 21776161 - 2¹⁹ = 21251873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21776141) 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, 7701 + ... + 10141.

It is an arithmetic number, because the mean of its divisors is an integer number (2974356).

Almost surely, 2^21776161 is an apocalyptic number.

It is an amenable number.

21776161 is a deficient number, since it is larger than the sum of its proper divisors (2018687).

21776161 is a wasteful number, since it uses less digits than its factorization.

21776161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3263.

The product of its digits is 3528, while the sum is 31.

The square root of 21776161 is about 4666.4934372610. The cubic root of 21776161 is about 279.2503801022.

It can be divided in two parts, 2177 and 6161, that added together give a palindrome (8338).

The spelling of 21776161 in words is "twenty-one million, seven hundred seventy-six thousand, one hundred sixty-one".