21115648 has 18 divisors (see below), whose sum is σ = 42149324. Its totient is φ = 10557696.

The previous prime is 21115603. The next prime is 21115651. The reversal of 21115648 is 84651112.

It is a super-3 number, since 3×21115648³ (a number of 23 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40986 + ... + 41497.

Almost surely, 2^21115648 is an apocalyptic number.

It is an amenable number.

21115648 is a deficient number, since it is larger than the sum of its proper divisors (21033676).

21115648 is an frugal number, since it uses more digits than its factorization.

21115648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82499 (or 82485 counting only the distinct ones).

The product of its digits is 1920, while the sum is 28.

The square root of 21115648 is about 4595.1766016117. The cubic root of 21115648 is about 276.3979416829.

The spelling of 21115648 in words is "twenty-one million, one hundred fifteen thousand, six hundred forty-eight".