21191244 has 24 divisors (see below), whose sum is σ = 49674240. Its totient is φ = 7031184.

The previous prime is 21191239. The next prime is 21191263. The reversal of 21191244 is 44219112.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1284 + ... + 6635.

It is an arithmetic number, because the mean of its divisors is an integer number (2069760).

Almost surely, 2^21191244 is an apocalyptic number.

It is an amenable number.

21191244 is an abundant number, since it is smaller than the sum of its proper divisors (28482996).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21191244 is a wasteful number, since it uses less digits than its factorization.

21191244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8149 (or 8147 counting only the distinct ones).

The product of its digits is 576, while the sum is 24.

The square root of 21191244 is about 4603.3948342500. The cubic root of 21191244 is about 276.7273923573.

The spelling of 21191244 in words is "twenty-one million, one hundred ninety-one thousand, two hundred forty-four".