21911669 has 8 divisors (see below), whose sum is σ = 23637432. Its totient is φ = 20191680.

The previous prime is 21911651. The next prime is 21911683. The reversal of 21911669 is 96611912.

It can be written as a sum of positive squares in 4 ways, for example, as 168100 + 21743569 = 410^2 + 4663^2 .

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 21911669 - 2¹² = 21907573 is a prime.

It is a super-2 number, since 2×21911669² = 960242476731122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21911689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9647 + ... + 11699.

It is an arithmetic number, because the mean of its divisors is an integer number (2954679).

Almost surely, 2^21911669 is an apocalyptic number.

It is an amenable number.

21911669 is a deficient number, since it is larger than the sum of its proper divisors (1725763).

21911669 is a wasteful number, since it uses less digits than its factorization.

21911669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2887.

The product of its digits is 5832, while the sum is 35.

The square root of 21911669 is about 4680.9901730296. The cubic root of 21911669 is about 279.8284195390.

The spelling of 21911669 in words is "twenty-one million, nine hundred eleven thousand, six hundred sixty-nine".