21670244 has 12 divisors (see below), whose sum is σ = 38064768. Its totient is φ = 10794600.

The previous prime is 21670219. The next prime is 21670283. The reversal of 21670244 is 44207612.

It is a super-5 number, since 5×21670244⁵ (a number of 38 digits) contains 55555 as substring.

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 3 ways as a sum of consecutive naturals, for example, 8912 + ... + 11079.

It is an arithmetic number, because the mean of its divisors is an integer number (3172064).

Almost surely, 2^21670244 is an apocalyptic number.

It is an amenable number.

21670244 is a deficient number, since it is larger than the sum of its proper divisors (16394524).

21670244 is a wasteful number, since it uses less digits than its factorization.

21670244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20266 (or 20264 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 21670244 is about 4655.1309326377. The cubic root of 21670244 is about 278.7968957276.

Adding to 21670244 its reverse (44207612), we get a palindrome (65877856).

The spelling of 21670244 in words is "twenty-one million, six hundred seventy thousand, two hundred forty-four".