2001002121 has 12 divisors (see below), whose sum is σ = 2944871748. Its totient is φ = 1308831264.

The previous prime is 2001002077. The next prime is 2001002137. The reversal of 2001002121 is 1212001002.

It can be written as a sum of positive squares in 2 ways, for example, as 1229273721 + 771728400 = 35061^2 + 27780^2 .

It is not a de Polignac number, because 2001002121 - 2⁶ = 2001002057 is a prime.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2001002821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2097010 + ... + 2097963.

It is an arithmetic number, because the mean of its divisors is an integer number (245405979).

Almost surely, 2^2001002121 is an apocalyptic number.

It is an amenable number.

2001002121 is a deficient number, since it is larger than the sum of its proper divisors (943869627).

2001002121 is a wasteful number, since it uses less digits than its factorization.

2001002121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4195032 (or 4195029 counting only the distinct ones).

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

The square root of 2001002121 is about 44732.5622002585. The cubic root of 2001002121 is about 1260.1314469820.

Adding to 2001002121 its reverse (1212001002), we get a palindrome (3213003123).

It can be divided in two parts, 2001002 and 121, that multiplied together give a palindrome (242121242).

The spelling of 2001002121 in words is "two billion, one million, two thousand, one hundred twenty-one".