391894417 has 8 divisors (see below), whose sum is σ = 404062056. Its totient is φ = 379809792.

The previous prime is 391894411. The next prime is 391894427. The reversal of 391894417 is 714498193.

It can be written as a sum of positive squares in 4 ways, for example, as 370216081 + 21678336 = 19241^2 + 4656^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 391894417 - 2⁷ = 391894289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391894411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11098 + ... + 30115.

It is an arithmetic number, because the mean of its divisors is an integer number (50507757).

Almost surely, 2^391894417 is an apocalyptic number.

391894417 is a gapful number since it is divisible by the number (37) formed by its first and last digit.

It is an amenable number.

391894417 is a deficient number, since it is larger than the sum of its proper divisors (12167639).

391894417 is a wasteful number, since it uses less digits than its factorization.

391894417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41507.

The product of its digits is 217728, while the sum is 46.

The square root of 391894417 is about 19796.3233202532. The cubic root of 391894417 is about 731.7954285407.

The spelling of 391894417 in words is "three hundred ninety-one million, eight hundred ninety-four thousand, four hundred seventeen".