1211212110021 has 32 divisors (see below), whose sum is σ = 1701047647488. Its totient is φ = 765587842560.

The previous prime is 1211212110013. The next prime is 1211212110089. The reversal of 1211212110021 is 1200112121121.

It is a happy number.

It is not a de Polignac number, because 1211212110021 - 2³ = 1211212110013 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211212110421) 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 31 ways as a sum of consecutive naturals, for example, 3726000 + ... + 4038006.

It is an arithmetic number, because the mean of its divisors is an integer number (53157738984).

Almost surely, 2^{1211212110021} is an apocalyptic number.

It is an amenable number.

1211212110021 is a deficient number, since it is larger than the sum of its proper divisors (489835537467).

1211212110021 is a wasteful number, since it uses less digits than its factorization.

1211212110021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312941.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1211212110021 its reverse (1200112121121), we get a palindrome (2411324231142).

It can be divided in two parts, 12112121100 and 21, that added together give a palindrome (12112121121).

The spelling of 1211212110021 in words is "one trillion, two hundred eleven billion, two hundred twelve million, one hundred ten thousand, twenty-one".