391669447 has 16 divisors (see below), whose sum is σ = 441635040. Its totient is φ = 344840832.

The previous prime is 391669427. The next prime is 391669459. The reversal of 391669447 is 744966193.

It is a cyclic number.

It is not a de Polignac number, because 391669447 - 2⁷ = 391669319 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 391669447.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391669427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25033 + ... + 37549.

It is an arithmetic number, because the mean of its divisors is an integer number (27602190).

Almost surely, 2^391669447 is an apocalyptic number.

391669447 is the 12517-th heptagonal number.

391669447 is a deficient number, since it is larger than the sum of its proper divisors (49965593).

391669447 is a wasteful number, since it uses less digits than its factorization.

391669447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12642.

The product of its digits is 979776, while the sum is 49.

The square root of 391669447 is about 19790.6403888303. The cubic root of 391669447 is about 731.6553708081.

The spelling of 391669447 in words is "three hundred ninety-one million, six hundred sixty-nine thousand, four hundred forty-seven".