501010721 has 2 divisors, whose sum is σ = 501010722. Its totient is φ = 501010720.

The previous prime is 501010709. The next prime is 501010739. The reversal of 501010721 is 127010105.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 409617121 + 91393600 = 20239^2 + 9560^2 .

It is a cyclic number.

It is not a de Polignac number, because 501010721 - 2¹⁰ = 501009697 is a prime.

It is a Sophie Germain prime.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 501010721.

It is not a weakly prime, because it can be changed into another prime (501010921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 250505360 + 250505361.

It is an arithmetic number, because the mean of its divisors is an integer number (250505361).

Almost surely, 2^501010721 is an apocalyptic number.

It is an amenable number.

501010721 is a deficient number, since it is larger than the sum of its proper divisors (1).

501010721 is an equidigital number, since it uses as much as digits as its factorization.

501010721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 70, while the sum is 17.

The square root of 501010721 is about 22383.2687737962. The cubic root of 501010721 is about 794.2349725543.

Adding to 501010721 its reverse (127010105), we get a palindrome (628020826).

The spelling of 501010721 in words is "five hundred one million, ten thousand, seven hundred twenty-one".