211221161100 has 216 divisors, whose sum is σ = 668424666000. Its totient is φ = 55786199040.

The previous prime is 211221161033. The next prime is 211221161153. The reversal of 211221161100 is 1161122112.

211221161100 is a `hidden beast` number, since 21 + 1 + 22 + 11 + 611 + 0 + 0 = 666.

It is a super-2 number, since 2×211221161100² (a number of 23 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 61524984 + ... + 61528416.

Almost surely, 2^211221161100 is an apocalyptic number.

211221161100 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 211221161100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (334212333000).

211221161100 is an abundant number, since it is smaller than the sum of its proper divisors (457203504900).

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

211221161100 is a wasteful number, since it uses less digits than its factorization.

211221161100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4089 (or 4079 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 18.

Adding to 211221161100 its reverse (1161122112), we get a palindrome (212382283212).

It can be divided in two parts, 21122116 and 1100, that added together give a square (21123216 = 4596²).

The spelling of 211221161100 in words is "two hundred eleven billion, two hundred twenty-one million, one hundred sixty-one thousand, one hundred".