21055748 has 24 divisors (see below), whose sum is σ = 42504000. Its totient is φ = 8939808.

The previous prime is 21055739. The next prime is 21055759. The reversal of 21055748 is 84755012.

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 7 ways as a sum of consecutive naturals, for example, 398 + ... + 6501.

It is an arithmetic number, because the mean of its divisors is an integer number (1771000).

Almost surely, 2^21055748 is an apocalyptic number.

21055748 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21055748 is an abundant number, since it is smaller than the sum of its proper divisors (21448252).

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

21055748 is a wasteful number, since it uses less digits than its factorization.

21055748 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7019 (or 7017 counting only the distinct ones).

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 21055748 is about 4588.6542689551. The cubic root of 21055748 is about 276.1363360595.

The spelling of 21055748 in words is "twenty-one million, fifty-five thousand, seven hundred forty-eight".