355881720721 has 2 divisors, whose sum is σ = 355881720722. Its totient is φ = 355881720720.

The previous prime is 355881720707. The next prime is 355881720749. The reversal of 355881720721 is 127027188553.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 352967880321 + 2913840400 = 594111^2 + 53980^2 .

It is a cyclic number.

It is not a de Polignac number, because 355881720721 - 2²⁹ = 355344849809 is a prime.

It is not a weakly prime, because it can be changed into another prime (355881720751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 177940860360 + 177940860361.

It is an arithmetic number, because the mean of its divisors is an integer number (177940860361).

Almost surely, 2^355881720721 is an apocalyptic number.

It is an amenable number.

355881720721 is a deficient number, since it is larger than the sum of its proper divisors (1).

355881720721 is an equidigital number, since it uses as much as digits as its factorization.

355881720721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 940800, while the sum is 49.

The spelling of 355881720721 in words is "three hundred fifty-five billion, eight hundred eighty-one million, seven hundred twenty thousand, seven hundred twenty-one".