21644048 has 10 divisors (see below), whose sum is σ = 41935374. Its totient is φ = 10822016.

The previous prime is 21644047. The next prime is 21644053. The reversal of 21644048 is 84044612.

It can be written as a sum of positive squares in only one way, i.e., 18079504 + 3564544 = 4252^2 + 1888^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21644048.

It is not an unprimeable number, because it can be changed into a prime (21644041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 676361 + ... + 676392.

Almost surely, 2^21644048 is an apocalyptic number.

It is an amenable number.

21644048 is a deficient number, since it is larger than the sum of its proper divisors (20291326).

21644048 is a wasteful number, since it uses less digits than its factorization.

21644048 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1352761 (or 1352755 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 29.

The square root of 21644048 is about 4652.3164122832. The cubic root of 21644048 is about 278.6845095398.

The spelling of 21644048 in words is "twenty-one million, six hundred forty-four thousand, forty-eight".