2001122021 has 4 divisors (see below), whose sum is σ = 2001214944. Its totient is φ = 2001029100.

The previous prime is 2001121999. The next prime is 2001122069. The reversal of 2001122021 is 1202211002.

It is a happy number.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1202211002 = 2 ⋅601105501.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001122021 is a prime.

It is a super-2 number, since 2×2001122021² = 8008978685862248882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2001121993 and 2001122011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001122621) 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, 4406 + ... + 63416.

It is an arithmetic number, because the mean of its divisors is an integer number (500303736).

Almost surely, 2^2001122021 is an apocalyptic number.

It is an amenable number.

2001122021 is a deficient number, since it is larger than the sum of its proper divisors (92923).

2001122021 is an equidigital number, since it uses as much as digits as its factorization.

2001122021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92922.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 2001122021 is about 44733.9023672203. The cubic root of 2001122021 is about 1260.1566154948.

Adding to 2001122021 its reverse (1202211002), we get a palindrome (3203333023).

The spelling of 2001122021 in words is "two billion, one million, one hundred twenty-two thousand, twenty-one".