21004648 has 16 divisors (see below), whose sum is σ = 45010080. Its totient is φ = 9001968.

The previous prime is 21004631. The next prime is 21004651. The reversal of 21004648 is 84640012.

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 in 3 ways as a sum of consecutive naturals, for example, 187486 + ... + 187597.

It is an arithmetic number, because the mean of its divisors is an integer number (2813130).

Almost surely, 2^21004648 is an apocalyptic number.

21004648 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21004648 is an abundant number, since it is smaller than the sum of its proper divisors (24005432).

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

21004648 is a wasteful number, since it uses less digits than its factorization.

21004648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375096 (or 375092 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 21004648 is about 4583.0828052742. The cubic root of 21004648 is about 275.9127708660.

The spelling of 21004648 in words is "twenty-one million, four thousand, six hundred forty-eight".