1212100021 has 8 divisors (see below), whose sum is σ = 1323381600. Its totient is φ = 1101000240.

The previous prime is 1212100009. The next prime is 1212100027. The reversal of 1212100021 is 1200012121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1212100021 - 2¹¹ = 1212097973 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1212099980 and 1212100007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212100027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31311 + ... + 58348.

It is an arithmetic number, because the mean of its divisors is an integer number (165422700).

Almost surely, 2^1212100021 is an apocalyptic number.

1212100021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1212100021 is a deficient number, since it is larger than the sum of its proper divisors (111281579).

1212100021 is a wasteful number, since it uses less digits than its factorization.

1212100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90899.

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

The square root of 1212100021 is about 34815.2268555010. The cubic root of 1212100021 is about 1066.2183507394.

Adding to 1212100021 its reverse (1200012121), we get a palindrome (2412112142).

The spelling of 1212100021 in words is "one billion, two hundred twelve million, one hundred thousand, twenty-one".