21655050 has 48 divisors (see below), whose sum is σ = 55448832. Its totient is φ = 5587200.

The previous prime is 21655043. The next prime is 21655063. The reversal of 21655050 is 5055612.

It is a self number, because there is not a number n which added to its sum of digits gives 21655050.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2322 + ... + 6978.

It is an arithmetic number, because the mean of its divisors is an integer number (1155184).

Almost surely, 2^21655050 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21655050, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27724416).

21655050 is an abundant number, since it is smaller than the sum of its proper divisors (33793782).

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

21655050 is a wasteful number, since it uses less digits than its factorization.

21655050 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4703 (or 4698 counting only the distinct ones).

The product of its (nonzero) digits is 1500, while the sum is 24.

The square root of 21655050 is about 4653.4986837862. The cubic root of 21655050 is about 278.7317214046.

The spelling of 21655050 in words is "twenty-one million, six hundred fifty-five thousand, fifty".