501001021 has 2 divisors, whose sum is σ = 501001022. Its totient is φ = 501001020.

The previous prime is 501001001. The next prime is 501001049. The reversal of 501001021 is 120100105.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 339075396 + 161925625 = 18414^2 + 12725^2 .

It is a cyclic number.

It is not a de Polignac number, because 501001021 - 2⁵ = 501000989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 501000989 and 501001007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (501001001) 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, 250500510 + 250500511.

It is an arithmetic number, because the mean of its divisors is an integer number (250500511).

Almost surely, 2^501001021 is an apocalyptic number.

It is an amenable number.

501001021 is a deficient number, since it is larger than the sum of its proper divisors (1).

501001021 is an equidigital number, since it uses as much as digits as its factorization.

501001021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10, while the sum is 10.

The square root of 501001021 is about 22383.0520930458. The cubic root of 501001021 is about 794.2298468297.

Adding to 501001021 its reverse (120100105), we get a palindrome (621101126).

The spelling of 501001021 in words is "five hundred one million, one thousand, twenty-one".