501040021 has 2 divisors, whose sum is σ = 501040022. Its totient is φ = 501040020.

The previous prime is 501039991. The next prime is 501040061. The reversal of 501040021 is 120040105.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 478996996 + 22043025 = 21886^2 + 4695^2 .

It is a cyclic number.

It is not a de Polignac number, because 501040021 - 2⁹ = 501039509 is a prime.

It is a super-2 number, since 2×501040021² = 502082205287360882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 501039983 and 501040010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (501040061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 250520010 + 250520011.

It is an arithmetic number, because the mean of its divisors is an integer number (250520011).

Almost surely, 2^501040021 is an apocalyptic number.

It is an amenable number.

501040021 is a deficient number, since it is larger than the sum of its proper divisors (1).

501040021 is an equidigital number, since it uses as much as digits as its factorization.

501040021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 501040021 is about 22383.9232709550. The cubic root of 501040021 is about 794.2504550115.

Adding to 501040021 its reverse (120040105), we get a palindrome (621080126).

The spelling of 501040021 in words is "five hundred one million, forty thousand, twenty-one".