1002002121 has 6 divisors (see below), whose sum is σ = 1447336410. Its totient is φ = 668001408.

The previous prime is 1002002093. The next prime is 1002002123. The reversal of 1002002121 is 1212002001.

It can be written as a sum of positive squares in only one way, i.e., 780587721 + 221414400 = 27939^2 + 14880^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1002002121 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 111333569 = 1002002121 / (1 + 0 + 0 + 2 + 0 + 0 + 2 + 1 + 2 + 1).

It is not an unprimeable number, because it can be changed into a prime (1002002123) 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, 55666776 + ... + 55666793.

It is an arithmetic number, because the mean of its divisors is an integer number (241222735).

Almost surely, 2^1002002121 is an apocalyptic number.

It is an amenable number.

1002002121 is a deficient number, since it is larger than the sum of its proper divisors (445334289).

1002002121 is a wasteful number, since it uses less digits than its factorization.

1002002121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111333575 (or 111333572 counting only the distinct ones).

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

The square root of 1002002121 is about 31654.4170851400. The cubic root of 1002002121 is about 1000.6669287738. Note that the first 3 decimals are identical.

Adding to 1002002121 its reverse (1212002001), we get a palindrome (2214004122).

The spelling of 1002002121 in words is "one billion, two million, two thousand, one hundred twenty-one".