221212261240 has 64 divisors (see below), whose sum is σ = 506290176000. Its totient is φ = 86963418240.

The previous prime is 221212261211. The next prime is 221212261241. The reversal of 221212261240 is 42162212122.

It is a happy number.

221212261240 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221212261241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12071685 + ... + 12089995.

It is an arithmetic number, because the mean of its divisors is an integer number (7910784000).

Almost surely, 2^221212261240 is an apocalyptic number.

221212261240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221212261240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (253145088000).

221212261240 is an abundant number, since it is smaller than the sum of its proper divisors (285077914760).

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

221212261240 is a wasteful number, since it uses less digits than its factorization.

221212261240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23500 (or 23496 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

Adding to 221212261240 its reverse (42162212122), we get a palindrome (263374473362).

The spelling of 221212261240 in words is "two hundred twenty-one billion, two hundred twelve million, two hundred sixty-one thousand, two hundred forty".