391621706447 has 2 divisors, whose sum is σ = 391621706448. Its totient is φ = 391621706446.

The previous prime is 391621706431. The next prime is 391621706519. The reversal of 391621706447 is 744607126193.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 391621706447 - 2⁴ = 391621706431 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 391621706395 and 391621706404.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391621706407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195810853223 + 195810853224.

It is an arithmetic number, because the mean of its divisors is an integer number (195810853224).

Almost surely, 2^391621706447 is an apocalyptic number.

391621706447 is a deficient number, since it is larger than the sum of its proper divisors (1).

391621706447 is an equidigital number, since it uses as much as digits as its factorization.

391621706447 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1524096, while the sum is 50.

The spelling of 391621706447 in words is "three hundred ninety-one billion, six hundred twenty-one million, seven hundred six thousand, four hundred forty-seven".