121212100 has 18 divisors (see below), whose sum is σ = 263030474. Its totient is φ = 48484800.

The previous prime is 121212097. The next prime is 121212103. The reversal of 121212100 is 1212121.

It is an interprime number because it is at equal distance from previous prime (121212097) and next prime (121212103).

It can be written as a sum of positive squares in 3 ways, for example, as 2096704 + 119115396 = 1448^2 + 10914^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (121212103) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 605961 + ... + 606160.

Almost surely, 2^121212100 is an apocalyptic number.

121212100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121212100 is an abundant number, since it is smaller than the sum of its proper divisors (141818374).

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

121212100 is a wasteful number, since it uses less digits than its factorization.

121212100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1212135 (or 1212128 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 121212100 is about 11009.6366879203. The cubic root of 121212100 is about 494.8975742909.

Adding to 121212100 its reverse (1212121), we get a palindrome (122424221).

Multiplying 121212100 by its reverse (1212121), we get a square (146923731864100 = 12121210²).

121212100 divided by its reverse (1212121) gives a square (100 = 10²).

The spelling of 121212100 in words is "one hundred twenty-one million, two hundred twelve thousand, one hundred".