1000002001221 has 24 divisors (see below), whose sum is σ = 1445841161856. Its totient is φ = 666024942240.

The previous prime is 1000002001133. The next prime is 1000002001231. The reversal of 1000002001221 is 1221002000001.

It is not a de Polignac number, because 1000002001221 - 2⁹ = 1000002000709 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1000002001231) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 77978616 + ... + 77991438.

It is an arithmetic number, because the mean of its divisors is an integer number (60243381744).

Almost surely, 2^{1000002001221} is an apocalyptic number.

It is an amenable number.

1000002001221 is a deficient number, since it is larger than the sum of its proper divisors (445839160635).

1000002001221 is a wasteful number, since it uses less digits than its factorization.

1000002001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20513 (or 20510 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 1000002001221 its reverse (1221002000001), we get a palindrome (2221004001222).

The spelling of 1000002001221 in words is "one trillion, two million, one thousand, two hundred twenty-one".