221111001000 has 192 divisors, whose sum is σ = 767555128080. Its totient is φ = 57369254400.

The previous prime is 221111000993. The next prime is 221111001011. The reversal of 221111001000 is 100111122.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 35320691844 + 185790309156 = 187938^2 + 431034^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1002 + ... + 664998.

Almost surely, 2^221111001000 is an apocalyptic number.

221111001000 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 221111001000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (383777564040).

221111001000 is an abundant number, since it is smaller than the sum of its proper divisors (546444127080).

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

221111001000 is a wasteful number, since it uses less digits than its factorization.

221111001000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 664061 (or 664044 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 221111001000 its reverse (100111122), we get a palindrome (221211112122).

The spelling of 221111001000 in words is "two hundred twenty-one billion, one hundred eleven million, one thousand".