1212100221 has 32 divisors (see below), whose sum is σ = 1730792448. Its totient is φ = 751887360.

The previous prime is 1212100213. The next prime is 1212100229. The reversal of 1212100221 is 1220012121.

It is an interprime number because it is at equal distance from previous prime (1212100213) and next prime (1212100229).

It is not a de Polignac number, because 1212100221 - 2³ = 1212100213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1212100197 and 1212100206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212100229) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2240211 + ... + 2240751.

It is an arithmetic number, because the mean of its divisors is an integer number (54087264).

Almost surely, 2^1212100221 is an apocalyptic number.

It is an amenable number.

1212100221 is a deficient number, since it is larger than the sum of its proper divisors (518692227).

1212100221 is a wasteful number, since it uses less digits than its factorization.

1212100221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 981.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1212100221 is about 34815.2297278073. The cubic root of 1212100221 is about 1066.2184093824.

Adding to 1212100221 its reverse (1220012121), we get a palindrome (2432112342).

The spelling of 1212100221 in words is "one billion, two hundred twelve million, one hundred thousand, two hundred twenty-one".