221121100 has 18 divisors (see below), whose sum is σ = 479833004. Its totient is φ = 88448400.

The previous prime is 221121071. The next prime is 221121113. The reversal of 221121100 is 1121122.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1105506 + ... + 1105705.

Almost surely, 2^221121100 is an apocalyptic number.

221121100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221121100 is an abundant number, since it is smaller than the sum of its proper divisors (258711904).

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

221121100 is a wasteful number, since it uses less digits than its factorization.

221121100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2211225 (or 2211218 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 221121100 is about 14870.1412232702. The cubic root of 221121100 is about 604.7047713776.

Adding to 221121100 its reverse (1121122), we get a palindrome (222242222).

The spelling of 221121100 in words is "two hundred twenty-one million, one hundred twenty-one thousand, one hundred".