1211221210100 has 36 divisors (see below), whose sum is σ = 2867290939968. Its totient is φ = 440444076000.

The previous prime is 1211221210091. The next prime is 1211221210159. The reversal of 1211221210100 is 10121221121.

It is a super-2 number, since 2×1211221210100² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 550553996 + ... + 550556195.

Almost surely, 2^{1211221210100} is an apocalyptic number.

1211221210100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211221210100 is an abundant number, since it is smaller than the sum of its proper divisors (1656069729868).

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

1211221210100 is a wasteful number, since it uses less digits than its factorization.

1211221210100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1101110216 (or 1101110209 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 1211221210100 its reverse (10121221121), we get a palindrome (1221342431221).

It can be divided in two parts, 12112 and 21210100, that added together give a palindrome (21222212).

The spelling of 1211221210100 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, two hundred ten thousand, one hundred".