391327681 has 16 divisors (see below), whose sum is σ = 413449344. Its totient is φ = 369667584.

The previous prime is 391327679. The next prime is 391327691. The reversal of 391327681 is 186723193.

It is a cyclic number.

It is not a de Polignac number, because 391327681 - 2¹ = 391327679 is a prime.

It is a super-2 number, since 2×391327681² = 306274707833675522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391327691) 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, 1108401 + ... + 1108753.

It is an arithmetic number, because the mean of its divisors is an integer number (25840584).

Almost surely, 2^391327681 is an apocalyptic number.

It is an amenable number.

391327681 is a deficient number, since it is larger than the sum of its proper divisors (22121663).

391327681 is a wasteful number, since it uses less digits than its factorization.

391327681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840.

The product of its digits is 54432, while the sum is 40.

The square root of 391327681 is about 19782.0039682536. The cubic root of 391327681 is about 731.4424976840.

The spelling of 391327681 in words is "three hundred ninety-one million, three hundred twenty-seven thousand, six hundred eighty-one".