21672211 has 4 divisors (see below), whose sum is σ = 23642424. Its totient is φ = 19702000.

The previous prime is 21672191. The next prime is 21672221. The reversal of 21672211 is 11227612.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21672211 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21672221) 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 3 ways as a sum of consecutive naturals, for example, 985090 + ... + 985111.

It is an arithmetic number, because the mean of its divisors is an integer number (5910606).

Almost surely, 2^21672211 is an apocalyptic number.

21672211 is a deficient number, since it is larger than the sum of its proper divisors (1970213).

21672211 is a wasteful number, since it uses less digits than its factorization.

21672211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1970212.

The product of its digits is 336, while the sum is 22.

The square root of 21672211 is about 4655.3422000966. The cubic root of 21672211 is about 278.8053309026.

Adding to 21672211 its reverse (11227612), we get a palindrome (32899823).

It can be divided in two parts, 216 and 72211, that added together give a palindrome (72427).

The spelling of 21672211 in words is "twenty-one million, six hundred seventy-two thousand, two hundred eleven".