1201221100 has 36 divisors (see below), whose sum is σ = 2608513600. Its totient is φ = 480144960.

The previous prime is 1201221053. The next prime is 1201221107. The reversal of 1201221100 is 11221021.

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

It is not an unprimeable number, because it can be changed into a prime (1201221107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 172486 + ... + 179314.

Almost surely, 2^1201221100 is an apocalyptic number.

1201221100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1201221100 is an abundant number, since it is smaller than the sum of its proper divisors (1407292500).

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

1201221100 is a wasteful number, since it uses less digits than its factorization.

1201221100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8602 (or 8595 counting only the distinct ones).

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

The square root of 1201221100 is about 34658.6367302582. The cubic root of 1201221100 is about 1063.0188948728.

Adding to 1201221100 its reverse (11221021), we get a palindrome (1212442121).

The spelling of 1201221100 in words is "one billion, two hundred one million, two hundred twenty-one thousand, one hundred".