1221041100 has 36 divisors (see below), whose sum is σ = 3532879784. Its totient is φ = 325610880.

The previous prime is 1221041077. The next prime is 1221041117. The reversal of 1221041100 is 11401221.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2034769 + ... + 2035368.

Almost surely, 2^1221041100 is an apocalyptic number.

1221041100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221041100 is an abundant number, since it is smaller than the sum of its proper divisors (2311838684).

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

1221041100 is a wasteful number, since it uses less digits than its factorization.

1221041100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4070154 (or 4070147 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1221041100 is about 34943.3985181751. The cubic root of 1221041100 is about 1068.8335908081.

Adding to 1221041100 its reverse (11401221), we get a palindrome (1232442321).

The spelling of 1221041100 in words is "one billion, two hundred twenty-one million, forty-one thousand, one hundred".