1210121100 has 72 divisors (see below), whose sum is σ = 3890323920. Its totient is φ = 322698240.

The previous prime is 1210121063. The next prime is 1210121113. The reversal of 1210121100 is 11210121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 221397 + ... + 226796.

Almost surely, 2^1210121100 is an apocalyptic number.

1210121100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1210121100 is an abundant number, since it is smaller than the sum of its proper divisors (2680202820).

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

1210121100 is a wasteful number, since it uses less digits than its factorization.

1210121100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448216 (or 448203 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 1210121100 is about 34786.7949084132. The cubic root of 1210121100 is about 1065.6377850107.

Adding to 1210121100 its reverse (11210121), we get a palindrome (1221331221).

The spelling of 1210121100 in words is "one billion, two hundred ten million, one hundred twenty-one thousand, one hundred".