1211120100 has 90 divisors (see below), whose sum is σ = 3925999154. Its totient is φ = 322963200.

The previous prime is 1211120093. The next prime is 1211120123. The reversal of 1211120100 is 10211121.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 331167204 + 879952896 = 18198^2 + 29664^2 .

It is a tau number, because it is divible by the number of its divisors (90).

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

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 66661 + ... + 82860.

Almost surely, 2^1211120100 is an apocalyptic number.

1211120100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211120100 is an abundant number, since it is smaller than the sum of its proper divisors (2714879054).

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

1211120100 is a wasteful number, since it uses less digits than its factorization.

1211120100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149547 (or 149531 counting only the distinct ones).

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

The square root of 1211120100 is about 34801.1508430397. The cubic root of 1211120100 is about 1065.9309455695.

Adding to 1211120100 its reverse (10211121), we get a palindrome (1221331221).

The spelling of 1211120100 in words is "one billion, two hundred eleven million, one hundred twenty thousand, one hundred".