1221131123100 has 216 divisors, whose sum is σ = 4380709144448. Its totient is φ = 278710761600.

The previous prime is 1221131123083. The next prime is 1221131123119. The reversal of 1221131123100 is 13211311221.

1221131123100 is a `hidden beast` number, since 1 + 221 + 131 + 1 + 2 + 310 + 0 = 666.

It is a super-2 number, since 2×1221131123100² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 4213047 + ... + 4493553.

Almost surely, 2^{1221131123100} is an apocalyptic number.

1221131123100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221131123100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2190354572224).

1221131123100 is an abundant number, since it is smaller than the sum of its proper divisors (3159578021348).

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

1221131123100 is a wasteful number, since it uses less digits than its factorization.

1221131123100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281225 (or 281215 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

Adding to 1221131123100 its reverse (13211311221), we get a palindrome (1234342434321).

The spelling of 1221131123100 in words is "one trillion, two hundred twenty-one billion, one hundred thirty-one million, one hundred twenty-three thousand, one hundred".