721246261 has 2 divisors, whose sum is σ = 721246262. Its totient is φ = 721246260.

The previous prime is 721246237. The next prime is 721246333. The reversal of 721246261 is 162642127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 720922500 + 323761 = 26850^2 + 569^2 .

It is an emirp because it is prime and its reverse (162642127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721246261 - 2¹⁹ = 720721973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721246231) 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, 360623130 + 360623131.

It is an arithmetic number, because the mean of its divisors is an integer number (360623131).

Almost surely, 2^721246261 is an apocalyptic number.

It is an amenable number.

721246261 is a deficient number, since it is larger than the sum of its proper divisors (1).

721246261 is an equidigital number, since it uses as much as digits as its factorization.

721246261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 31.

The square root of 721246261 is about 26856.0283921506. The cubic root of 721246261 is about 896.7977808544.

Adding to 721246261 its reverse (162642127), we get a palindrome (883888388).

The spelling of 721246261 in words is "seven hundred twenty-one million, two hundred forty-six thousand, two hundred sixty-one".