721412565421 has 2 divisors, whose sum is σ = 721412565422. Its totient is φ = 721412565420.

The previous prime is 721412565409. The next prime is 721412565431. The reversal of 721412565421 is 124565214127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 705658801225 + 15753764196 = 840035^2 + 125514^2 .

It is a cyclic number.

It is not a de Polignac number, because 721412565421 - 2⁹ = 721412564909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721412565431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360706282710 + 360706282711.

It is an arithmetic number, because the mean of its divisors is an integer number (360706282711).

Almost surely, 2^721412565421 is an apocalyptic number.

It is an amenable number.

721412565421 is a deficient number, since it is larger than the sum of its proper divisors (1).

721412565421 is an equidigital number, since it uses as much as digits as its factorization.

721412565421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 134400, while the sum is 40.

Adding to 721412565421 its reverse (124565214127), we get a palindrome (845977779548).

The spelling of 721412565421 in words is "seven hundred twenty-one billion, four hundred twelve million, five hundred sixty-five thousand, four hundred twenty-one".