1774728721 has 2 divisors, whose sum is σ = 1774728722. Its totient is φ = 1774728720.

The previous prime is 1774728707. The next prime is 1774728733. The reversal of 1774728721 is 1278274771.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1773336321 + 1392400 = 42111^2 + 1180^2 .

It is an emirp because it is prime and its reverse (1278274771) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1774728721 - 2¹⁵ = 1774695953 is a prime.

It is not a weakly prime, because it can be changed into another prime (1774728701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 887364360 + 887364361.

It is an arithmetic number, because the mean of its divisors is an integer number (887364361).

Almost surely, 2^1774728721 is an apocalyptic number.

It is an amenable number.

1774728721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1774728721 is an equidigital number, since it uses as much as digits as its factorization.

1774728721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 307328, while the sum is 46.

The square root of 1774728721 is about 42127.5292534466. The cubic root of 1774728721 is about 1210.7207692576.

The spelling of 1774728721 in words is "one billion, seven hundred seventy-four million, seven hundred twenty-eight thousand, seven hundred twenty-one".