2001000123 has 12 divisors (see below), whose sum is σ = 2904860400. Its totient is φ = 1327295376.

The previous prime is 2001000101. The next prime is 2001000139. The reversal of 2001000123 is 3210001002.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-2001000123 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (2001000223) 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 11 ways as a sum of consecutive naturals, for example, 556836 + ... + 560417.

It is an arithmetic number, because the mean of its divisors is an integer number (242071700).

Almost surely, 2^2001000123 is an apocalyptic number.

2001000123 is a deficient number, since it is larger than the sum of its proper divisors (903860277).

2001000123 is a wasteful number, since it uses less digits than its factorization.

2001000123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1117458 (or 1117455 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 2001000123 is about 44732.5398675282. The cubic root of 2001000123 is about 1260.1310275682.

Adding to 2001000123 its reverse (3210001002), we get a palindrome (5211001125).

The spelling of 2001000123 in words is "two billion, one million, one hundred twenty-three", and thus it is an aban number.