21221967 has 16 divisors (see below), whose sum is σ = 32266080. Its totient is φ = 12291072.

The previous prime is 21221953. The next prime is 21222013. The reversal of 21221967 is 76912212.

It is a de Polignac number, because none of the positive numbers 2^k-21221967 is a prime.

It is a super-3 number, since 3×21221967³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221927) 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 15 ways as a sum of consecutive naturals, for example, 15342 + ... + 16667.

It is an arithmetic number, because the mean of its divisors is an integer number (2016630).

Almost surely, 2^21221967 is an apocalyptic number.

21221967 is a deficient number, since it is larger than the sum of its proper divisors (11044113).

21221967 is a wasteful number, since it uses less digits than its factorization.

21221967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32042.

The product of its digits is 3024, while the sum is 30.

The square root of 21221967 is about 4606.7306194307. The cubic root of 21221967 is about 276.8610606200.

The spelling of 21221967 in words is "twenty-one million, two hundred twenty-one thousand, nine hundred sixty-seven".