1000120021 has 2 divisors, whose sum is σ = 1000120022. Its totient is φ = 1000120020.

The previous prime is 1000120007. The next prime is 1000120049. The reversal of 1000120021 is 1200210001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 580279921 + 419840100 = 24089^2 + 20490^2 .

It is a cyclic number.

It is not a de Polignac number, because 1000120021 - 2¹⁷ = 999988949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1000119986 and 1000120013.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1000120001) 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 as a sum of consecutive naturals, namely, 500060010 + 500060011.

It is an arithmetic number, because the mean of its divisors is an integer number (500060011).

Almost surely, 2^1000120021 is an apocalyptic number.

It is an amenable number.

1000120021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1000120021 is an equidigital number, since it uses as much as digits as its factorization.

1000120021 is an odious number, because the sum of its binary digits is odd.

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

The square root of 1000120021 is about 31624.6742433815. The cubic root of 1000120021 is about 1000.0400053995.

Adding to 1000120021 its reverse (1200210001), we get a palindrome (2200330022).

The spelling of 1000120021 in words is "one billion, one hundred twenty thousand, twenty-one".