22121550 has 144 divisors (see below), whose sum is σ = 67026960. Its totient is φ = 5184000.

The previous prime is 22121543. The next prime is 22121563. The reversal of 22121550 is 5512122.

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

It is a congruent number.

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 71 ways as a sum of consecutive naturals, for example, 202896 + ... + 203004.

It is an arithmetic number, because the mean of its divisors is an integer number (465465).

Almost surely, 2^22121550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 22121550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33513480).

22121550 is an abundant number, since it is smaller than the sum of its proper divisors (44905410).

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

22121550 is a wasteful number, since it uses less digits than its factorization.

22121550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179 (or 171 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 22121550 is about 4703.3551853969. The cubic root of 22121550 is about 280.7190278376.

Adding to 22121550 its reverse (5512122), we get a palindrome (27633672).

The spelling of 22121550 in words is "twenty-two million, one hundred twenty-one thousand, five hundred fifty".