1212121100 has 18 divisors (see below), whose sum is σ = 2630303004. Its totient is φ = 484848400.

The previous prime is 1212121069. The next prime is 1212121121. The reversal of 1212121100 is 11212121.

It is a super-2 number, since 2×1212121100² = 2938475122130420000, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6060506 + ... + 6060705.

Almost surely, 2^1212121100 is an apocalyptic number.

1212121100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1212121100 is an abundant number, since it is smaller than the sum of its proper divisors (1418181904).

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

1212121100 is a wasteful number, since it uses less digits than its factorization.

1212121100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12121225 (or 12121218 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 1212121100 is about 34815.5295809212. The cubic root of 1212121100 is about 1066.2245313862.

Adding to 1212121100 its reverse (11212121), we get a palindrome (1223333221).

The spelling of 1212121100 in words is "one billion, two hundred twelve million, one hundred twenty-one thousand, one hundred".