391105060721 has 2 divisors, whose sum is σ = 391105060722. Its totient is φ = 391105060720.

The previous prime is 391105060691. The next prime is 391105060727. The reversal of 391105060721 is 127060501193.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 196923825121 + 194181235600 = 443761^2 + 440660^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-391105060721 is a prime.

It is not a weakly prime, because it can be changed into another prime (391105060727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195552530360 + 195552530361.

It is an arithmetic number, because the mean of its divisors is an integer number (195552530361).

Almost surely, 2^391105060721 is an apocalyptic number.

It is an amenable number.

391105060721 is a deficient number, since it is larger than the sum of its proper divisors (1).

391105060721 is an equidigital number, since it uses as much as digits as its factorization.

391105060721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11340, while the sum is 35.

The spelling of 391105060721 in words is "three hundred ninety-one billion, one hundred five million, sixty thousand, seven hundred twenty-one".