1221003002100 has 288 divisors, whose sum is σ = 4253216665600. Its totient is φ = 264194265600.

The previous prime is 1221003002057. The next prime is 1221003002101. The reversal of 1221003002100 is 12003001221.

It is a super-2 number, since 2×1221003002100² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221003002101) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 55090821 + ... + 55112979.

Almost surely, 2^{1221003002100} is an apocalyptic number.

1221003002100 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 1221003002100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2126608332800).

1221003002100 is an abundant number, since it is smaller than the sum of its proper divisors (3032213663500).

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

1221003002100 is a wasteful number, since it uses less digits than its factorization.

1221003002100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23583 (or 23576 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 1221003002100 its reverse (12003001221), we get a palindrome (1233006003321).

The spelling of 1221003002100 in words is "one trillion, two hundred twenty-one billion, three million, two thousand, one hundred".