21611673 has 12 divisors (see below), whose sum is σ = 31302180. Its totient is φ = 14368416.

The previous prime is 21611669. The next prime is 21611687. The reversal of 21611673 is 37611612.

It can be written as a sum of positive squares in 2 ways, for example, as 1871424 + 19740249 = 1368^2 + 4443^2 .

It is not a de Polignac number, because 21611673 - 2² = 21611669 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21611693) 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 11 ways as a sum of consecutive naturals, for example, 415 + ... + 6587.

It is an arithmetic number, because the mean of its divisors is an integer number (2608515).

Almost surely, 2^21611673 is an apocalyptic number.

It is an amenable number.

21611673 is a deficient number, since it is larger than the sum of its proper divisors (9690507).

21611673 is a wasteful number, since it uses less digits than its factorization.

21611673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6568 (or 6565 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 21611673 is about 4648.8356606789. The cubic root of 21611673 is about 278.5454888216.

The spelling of 21611673 in words is "twenty-one million, six hundred eleven thousand, six hundred seventy-three".