503500021 has 2 divisors, whose sum is σ = 503500022. Its totient is φ = 503500020.

The previous prime is 503500007. The next prime is 503500027. The reversal of 503500021 is 120005305.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 322597521 + 180902500 = 17961^2 + 13450^2 .

It is a cyclic number.

It is not a de Polignac number, because 503500021 - 2¹⁵ = 503467253 is a prime.

It is a super-2 number, since 2×503500021² = 507024542294000882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 503499968 and 503500004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (503500027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 251750010 + 251750011.

It is an arithmetic number, because the mean of its divisors is an integer number (251750011).

Almost surely, 2^503500021 is an apocalyptic number.

It is an amenable number.

503500021 is a deficient number, since it is larger than the sum of its proper divisors (1).

503500021 is an equidigital number, since it uses as much as digits as its factorization.

503500021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 150, while the sum is 16.

The square root of 503500021 is about 22438.8061402562. The cubic root of 503500021 is about 795.5482004068.

Adding to 503500021 its reverse (120005305), we get a palindrome (623505326).

The spelling of 503500021 in words is "five hundred three million, five hundred thousand, twenty-one".