2001011021 has 4 divisors (see below), whose sum is σ = 2002012032. Its totient is φ = 2000010012.

The previous prime is 2001011003. The next prime is 2001011029. The reversal of 2001011021 is 1201101002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1201101002 = 2 ⋅600550501.

It is a cyclic number.

It is not a de Polignac number, because 2001011021 - 2³⁰ = 927269197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001011029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 497501 + ... + 501506.

It is an arithmetic number, because the mean of its divisors is an integer number (500503008).

Almost surely, 2^2001011021 is an apocalyptic number.

It is an amenable number.

2001011021 is a deficient number, since it is larger than the sum of its proper divisors (1001011).

2001011021 is an equidigital number, since it uses as much as digits as its factorization.

2001011021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1001010.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 2001011021 is about 44732.6616802533. The cubic root of 2001011021 is about 1260.1333152381.

Adding to 2001011021 its reverse (1201101002), we get a palindrome (3202112023).

The spelling of 2001011021 in words is "two billion, one million, eleven thousand, twenty-one".