721522522451261 has 2 divisors, whose sum is σ = 721522522451262. Its totient is φ = 721522522451260.

The previous prime is 721522522451257. The next prime is 721522522451273. The reversal of 721522522451261 is 162154225225127.

It is a happy number.

721522522451261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 690192027508036 + 31330494943225 = 26271506^2 + 5597365^2 .

It is a cyclic number.

It is not a de Polignac number, because 721522522451261 - 2² = 721522522451257 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721522522451161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360761261225630 + 360761261225631.

It is an arithmetic number, because the mean of its divisors is an integer number (360761261225631).

Almost surely, 2^{721522522451261} is an apocalyptic number.

It is an amenable number.

721522522451261 is a deficient number, since it is larger than the sum of its proper divisors (1).

721522522451261 is an equidigital number, since it uses as much as digits as its factorization.

721522522451261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1344000, while the sum is 47.

Adding to 721522522451261 its reverse (162154225225127), we get a palindrome (883676747676388).

The spelling of 721522522451261 in words is "seven hundred twenty-one trillion, five hundred twenty-two billion, five hundred twenty-two million, four hundred fifty-one thousand, two hundred sixty-one".