1211125100 has 72 divisors (see below), whose sum is σ = 2727825408. Its totient is φ = 466401600.

The previous prime is 1211125087. The next prime is 1211125133. The reversal of 1211125100 is 15211121.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 303317 + ... + 307283.

It is an arithmetic number, because the mean of its divisors is an integer number (37886464).

Almost surely, 2^1211125100 is an apocalyptic number.

1211125100 is a gapful number since it is divisible by the number (10) 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 1211125100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1363912704).

1211125100 is an abundant number, since it is smaller than the sum of its proper divisors (1516700308).

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

1211125100 is a wasteful number, since it uses less digits than its factorization.

1211125100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4095 (or 4088 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 14.

The square root of 1211125100 is about 34801.2226796703. Note that the first 3 decimals coincide. The cubic root of 1211125100 is about 1065.9324124340.

Adding to 1211125100 its reverse (15211121), we get a palindrome (1226336221).

The spelling of 1211125100 in words is "one billion, two hundred eleven million, one hundred twenty-five thousand, one hundred".