391481939 has 4 divisors (see below), whose sum is σ = 393041880. Its totient is φ = 389922000.

The previous prime is 391481929. The next prime is 391481953. The reversal of 391481939 is 939184193.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 391481939 - 2²⁰ = 390433363 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 391481893 and 391481902.

It is not an unprimeable number, because it can be changed into a prime (391481929) 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, 779594 + ... + 780095.

It is an arithmetic number, because the mean of its divisors is an integer number (98260470).

Almost surely, 2^391481939 is an apocalyptic number.

391481939 is a deficient number, since it is larger than the sum of its proper divisors (1559941).

391481939 is a wasteful number, since it uses less digits than its factorization.

391481939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1559940.

The product of its digits is 209952, while the sum is 47.

The square root of 391481939 is about 19785.9025318533. The cubic root of 391481939 is about 731.5385945016.

The spelling of 391481939 in words is "three hundred ninety-one million, four hundred eighty-one thousand, nine hundred thirty-nine".