1221002102021 has 6 divisors (see below), whose sum is σ = 1322150205330. Its totient is φ = 1127078863248.

The previous prime is 1221002101997. The next prime is 1221002102029. The reversal of 1221002102021 is 1202012001221.

It can be written as a sum of positive squares in 3 ways, for example, as 29060020900 + 1191942081121 = 170470^2 + 1091761^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1221002102021 is a prime.

It is a super-2 number, since 2×1221002102021² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1221002101987 and 1221002102005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221002102029) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3612432086 + ... + 3612432423.

It is an arithmetic number, because the mean of its divisors is an integer number (220358367555).

Almost surely, 2^{1221002102021} is an apocalyptic number.

It is an amenable number.

1221002102021 is a deficient number, since it is larger than the sum of its proper divisors (101148103309).

1221002102021 is an equidigital number, since it uses as much as digits as its factorization.

1221002102021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7224864535 (or 7224864522 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 1221002102021 its reverse (1202012001221), we get a palindrome (2423014103242).

The spelling of 1221002102021 in words is "one trillion, two hundred twenty-one billion, two million, one hundred two thousand, twenty-one".