21068644 has 48 divisors (see below), whose sum is σ = 42940800. Its totient is φ = 8971776.

The previous prime is 21068617. The next prime is 21068653. The reversal of 21068644 is 44686012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29362 + ... + 30070.

It is an arithmetic number, because the mean of its divisors is an integer number (894600).

Almost surely, 2^21068644 is an apocalyptic number.

It is an amenable number.

21068644 is an abundant number, since it is smaller than the sum of its proper divisors (21872156).

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

21068644 is a wasteful number, since it uses less digits than its factorization.

21068644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 772 (or 770 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 31.

The square root of 21068644 is about 4590.0592588767. The cubic root of 21068644 is about 276.1926995669.

It can be divided in two parts, 21068 and 644, that added together give a palindrome (21712).

The spelling of 21068644 in words is "twenty-one million, sixty-eight thousand, six hundred forty-four".