21616771 has 16 divisors (see below), whose sum is σ = 24156000. Its totient is φ = 19340640.

The previous prime is 21616747. The next prime is 21616781. The reversal of 21616771 is 17761612.

It is not a de Polignac number, because 21616771 - 2⁷ = 21616643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21616781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 145005 + ... + 145153.

It is an arithmetic number, because the mean of its divisors is an integer number (1509750).

Almost surely, 2^21616771 is an apocalyptic number.

21616771 is a deficient number, since it is larger than the sum of its proper divisors (2539229).

21616771 is a wasteful number, since it uses less digits than its factorization.

21616771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291 (or 269 counting only the distinct ones).

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

The square root of 21616771 is about 4649.3839376846. The cubic root of 21616771 is about 278.5673892279.

The spelling of 21616771 in words is "twenty-one million, six hundred sixteen thousand, seven hundred seventy-one".