1213212100 has 36 divisors (see below), whose sum is σ = 2723458500. Its totient is φ = 468549760.

The previous prime is 1213212083. The next prime is 1213212107. The reversal of 1213212100 is 12123121.

It can be written as a sum of positive squares in 6 ways, for example, as 28751044 + 1184461056 = 5362^2 + 34416^2 .

It is not an unprimeable number, because it can be changed into a prime (1213212107) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 206275 + ... + 212074.

It is an arithmetic number, because the mean of its divisors is an integer number (75651625).

Almost surely, 2^1213212100 is an apocalyptic number.

1213212100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1213212100 is an abundant number, since it is smaller than the sum of its proper divisors (1510246400).

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

1213212100 is a wasteful number, since it uses less digits than its factorization.

1213212100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 418392 (or 418385 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1213212100 is about 34831.1943521895. The cubic root of 1213212100 is about 1066.5443295025.

Adding to 1213212100 its reverse (12123121), we get a palindrome (1225335221).

The spelling of 1213212100 in words is "one billion, two hundred thirteen million, two hundred twelve thousand, one hundred".