728421121 has 2 divisors, whose sum is σ = 728421122. Its totient is φ = 728421120.

The previous prime is 728421103. The next prime is 728421149. The reversal of 728421121 is 121124827.

It is an a-pointer prime, because the next prime (728421149) can be obtained adding 728421121 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 725548096 + 2873025 = 26936^2 + 1695^2 .

It is a cyclic number.

It is not a de Polignac number, because 728421121 - 2¹¹ = 728419073 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 728421121.

It is not a weakly prime, because it can be changed into another prime (728425121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 364210560 + 364210561.

It is an arithmetic number, because the mean of its divisors is an integer number (364210561).

Almost surely, 2^728421121 is an apocalyptic number.

It is an amenable number.

728421121 is a deficient number, since it is larger than the sum of its proper divisors (1).

728421121 is an equidigital number, since it uses as much as digits as its factorization.

728421121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1792, while the sum is 28.

The square root of 728421121 is about 26989.2778895620. The cubic root of 728421121 is about 899.7617151063.

Adding to 728421121 its reverse (121124827), we get a palindrome (849545948).

The spelling of 728421121 in words is "seven hundred twenty-eight million, four hundred twenty-one thousand, one hundred twenty-one".