503800021 has 2 divisors, whose sum is σ = 503800022. Its totient is φ = 503800020.

The previous prime is 503799971. The next prime is 503800051. The reversal of 503800021 is 120008305.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 367143921 + 136656100 = 19161^2 + 11690^2 .

It is a cyclic number.

It is not a de Polignac number, because 503800021 - 2⁷ = 503799893 is a prime.

It is a super-2 number, since 2×503800021² = 507628922319200882, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (503800051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 251900010 + 251900011.

It is an arithmetic number, because the mean of its divisors is an integer number (251900011).

Almost surely, 2^503800021 is an apocalyptic number.

It is an amenable number.

503800021 is a deficient number, since it is larger than the sum of its proper divisors (1).

503800021 is an equidigital number, since it uses as much as digits as its factorization.

503800021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 503800021 is about 22445.4899924239. The cubic root of 503800021 is about 795.7061726443.

Adding to 503800021 its reverse (120008305), we get a palindrome (623808326).

The spelling of 503800021 in words is "five hundred three million, eight hundred thousand, twenty-one".