21065648 has 10 divisors (see below), whose sum is σ = 40814724. Its totient is φ = 10532816.

The previous prime is 21065641. The next prime is 21065701. The reversal of 21065648 is 84656012.

It is a super-3 number, since 3×21065648³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21065641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 658286 + ... + 658317.

Almost surely, 2^21065648 is an apocalyptic number.

It is an amenable number.

21065648 is a deficient number, since it is larger than the sum of its proper divisors (19749076).

21065648 is a wasteful number, since it uses less digits than its factorization.

21065648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1316611 (or 1316605 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 21065648 is about 4589.7328898314. The cubic root of 21065648 is about 276.1796072427.

The spelling of 21065648 in words is "twenty-one million, sixty-five thousand, six hundred forty-eight".