1200001021 has 4 divisors (see below), whose sum is σ = 1217911552. Its totient is φ = 1182090492.

The previous prime is 1200001013. The next prime is 1200001051. The reversal of 1200001021 is 1201000021.

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.

It is a cyclic number.

It is not a de Polignac number, because 1200001021 - 2³ = 1200001013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1200000995 and 1200001013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1200001001) 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 3 ways as a sum of consecutive naturals, for example, 8955165 + ... + 8955298.

It is an arithmetic number, because the mean of its divisors is an integer number (304477888).

Almost surely, 2^1200001021 is an apocalyptic number.

It is an amenable number.

1200001021 is a deficient number, since it is larger than the sum of its proper divisors (17910531).

1200001021 is an equidigital number, since it uses as much as digits as its factorization.

1200001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17910530.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 1200001021 is about 34641.0308882400. The cubic root of 1200001021 is about 1062.6588705643.

Adding to 1200001021 its reverse (1201000021), we get a palindrome (2401001042).

The spelling of 1200001021 in words is "one billion, two hundred million, one thousand, twenty-one".