391449643 has 4 divisors (see below), whose sum is σ = 421561168. Its totient is φ = 361338120.

The previous prime is 391449637. The next prime is 391449697. The reversal of 391449643 is 346944193.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 346944193 = 683 ⋅507971.

It is not a de Polignac number, because 391449643 - 2¹³ = 391441451 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 391449643.

It is not an unprimeable number, because it can be changed into a prime (391449613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15055743 + ... + 15055768.

It is an arithmetic number, because the mean of its divisors is an integer number (105390292).

Almost surely, 2^391449643 is an apocalyptic number.

391449643 is a deficient number, since it is larger than the sum of its proper divisors (30111525).

391449643 is a wasteful number, since it uses less digits than its factorization.

391449643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30111524.

The product of its digits is 279936, while the sum is 43.

The square root of 391449643 is about 19785.0863783811. The cubic root of 391449643 is about 731.5184774219.

The spelling of 391449643 in words is "three hundred ninety-one million, four hundred forty-nine thousand, six hundred forty-three".