211221221000 has 128 divisors (see below), whose sum is σ = 497860927200. Its totient is φ = 83874995200.

The previous prime is 211221220913. The next prime is 211221221009. The reversal of 211221221000 is 122122112.

It can be written as a sum of positive squares in 16 ways, for example, as 97742519044 + 113478701956 = 312638^2 + 336866^2 .

It is a super-2 number, since 2×211221221000² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (211221221009) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 85271762 + ... + 85274238.

Almost surely, 2^211221221000 is an apocalyptic number.

211221221000 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 211221221000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (248930463600).

211221221000 is an abundant number, since it is smaller than the sum of its proper divisors (286639706200).

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

211221221000 is a wasteful number, since it uses less digits than its factorization.

211221221000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3084 (or 3070 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 211221221000 its reverse (122122112), we get a palindrome (211343343112).

The spelling of 211221221000 in words is "two hundred eleven billion, two hundred twenty-one million, two hundred twenty-one thousand".