21055050 has 72 divisors (see below), whose sum is σ = 57451680. Its totient is φ = 5527200.

The previous prime is 21055043. The next prime is 21055063. The reversal of 21055050 is 5055012.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 31621 + ... + 32279.

It is an arithmetic number, because the mean of its divisors is an integer number (797940).

Almost surely, 2^21055050 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21055050, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28725840).

21055050 is an abundant number, since it is smaller than the sum of its proper divisors (36396630).

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

21055050 is a wasteful number, since it uses less digits than its factorization.

21055050 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 748 (or 740 counting only the distinct ones).

The product of its (nonzero) digits is 250, while the sum is 18.

The square root of 21055050 is about 4588.5782111674. The cubic root of 21055050 is about 276.1332847107.

The spelling of 21055050 in words is "twenty-one million, fifty-five thousand, fifty".