391913446945 has 4 divisors (see below), whose sum is σ = 470296136340. Its totient is φ = 313530757552.

The previous prime is 391913446933. The next prime is 391913446949. The reversal of 391913446945 is 549644319193.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 549644319193 = 257 ⋅2138693849.

It can be written as a sum of positive squares in 2 ways, for example, as 276953797696 + 114959649249 = 526264^2 + 339057^2 .

It is a cyclic number.

It is not a de Polignac number, because 391913446945 - 2¹⁹ = 391912922657 is a prime.

It is a super-2 number, since 2×391913446945² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 391913446945.

It is not an unprimeable number, because it can be changed into a prime (391913446949) 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 in 3 ways as a sum of consecutive naturals, for example, 39191344690 + ... + 39191344699.

It is an arithmetic number, because the mean of its divisors is an integer number (117574034085).

Almost surely, 2^391913446945 is an apocalyptic number.

It is an amenable number.

391913446945 is a deficient number, since it is larger than the sum of its proper divisors (78382689395).

391913446945 is an equidigital number, since it uses as much as digits as its factorization.

391913446945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78382689394.

The product of its digits is 12597120, while the sum is 58.

The spelling of 391913446945 in words is "three hundred ninety-one billion, nine hundred thirteen million, four hundred forty-six thousand, nine hundred forty-five".