221012550 has 240 divisors, whose sum is σ = 691924464. Its totient is φ = 52272000.

The previous prime is 221012521. The next prime is 221012551. The reversal of 221012550 is 55210122.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221012551) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 5390530 + ... + 5390570.

Almost surely, 2^221012550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221012550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (345962232).

221012550 is an abundant number, since it is smaller than the sum of its proper divisors (470911914).

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

221012550 is a wasteful number, since it uses less digits than its factorization.

221012550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 62 counting only the distinct ones).

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

The square root of 221012550 is about 14866.4908435044. The cubic root of 221012550 is about 604.6058038178.

Adding to 221012550 its reverse (55210122), we get a palindrome (276222672).

The spelling of 221012550 in words is "two hundred twenty-one million, twelve thousand, five hundred fifty".