391838643 has 36 divisors (see below), whose sum is σ = 659816040. Its totient is φ = 223425216.

The previous prime is 391838641. The next prime is 391838693. The reversal of 391838643 is 346838193.

It is not a de Polignac number, because 391838643 - 2¹ = 391838641 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (391838641) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 346503 + ... + 347631.

Almost surely, 2^391838643 is an apocalyptic number.

391838643 is a deficient number, since it is larger than the sum of its proper divisors (267977397).

391838643 is a wasteful number, since it uses less digits than its factorization.

391838643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1936 (or 1926 counting only the distinct ones).

The product of its digits is 373248, while the sum is 45.

The square root of 391838643 is about 19794.9145742031. The cubic root of 391838643 is about 731.7607107758.

The spelling of 391838643 in words is "three hundred ninety-one million, eight hundred thirty-eight thousand, six hundred forty-three".