21022191 has 12 divisors (see below), whose sum is σ = 30444960. Its totient is φ = 13978080.

The previous prime is 21022171. The next prime is 21022193. The reversal of 21022191 is 19122012.

It is not a de Polignac number, because 21022191 - 2⁷ = 21022063 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022193) 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 11 ways as a sum of consecutive naturals, for example, 826 + ... + 6536.

It is an arithmetic number, because the mean of its divisors is an integer number (2537080).

Almost surely, 2^21022191 is an apocalyptic number.

21022191 is a deficient number, since it is larger than the sum of its proper divisors (9422769).

21022191 is a wasteful number, since it uses less digits than its factorization.

21022191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6126 (or 6123 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 21022191 is about 4584.9962922559. The cubic root of 21022191 is about 275.9895632474.

The spelling of 21022191 in words is "twenty-one million, twenty-two thousand, one hundred ninety-one".