1016257721 has 2 divisors, whose sum is σ = 1016257722. Its totient is φ = 1016257720.

The previous prime is 1016257709. The next prime is 1016257729. The reversal of 1016257721 is 1277526101.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 987216400 + 29041321 = 31420^2 + 5389^2 .

It is an emirp because it is prime and its reverse (1277526101) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1016257721 - 2¹⁸ = 1015995577 is a prime.

It is a super-2 number, since 2×1016257721² = 2065559510984227682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1016257729) 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, 508128860 + 508128861.

It is an arithmetic number, because the mean of its divisors is an integer number (508128861).

Almost surely, 2^1016257721 is an apocalyptic number.

It is an amenable number.

1016257721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1016257721 is an equidigital number, since it uses as much as digits as its factorization.

1016257721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5880, while the sum is 32.

The square root of 1016257721 is about 31878.7973581188. The cubic root of 1016257721 is about 1005.3901345817.

The spelling of 1016257721 in words is "one billion, sixteen million, two hundred fifty-seven thousand, seven hundred twenty-one".