391315481 has 4 divisors (see below), whose sum is σ = 393302052. Its totient is φ = 389328912.

The previous prime is 391315459. The next prime is 391315499. The reversal of 391315481 is 184513193.

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

It can be written as a sum of positive squares in 2 ways, for example, as 384787456 + 6528025 = 19616^2 + 2555^2 .

It is a cyclic number.

It is not a de Polignac number, because 391315481 - 2²² = 387121177 is a prime.

It is a super-2 number, since 2×391315481² = 306255611340522722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (391315411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 992990 + ... + 993383.

It is an arithmetic number, because the mean of its divisors is an integer number (98325513).

Almost surely, 2^391315481 is an apocalyptic number.

It is an amenable number.

391315481 is a deficient number, since it is larger than the sum of its proper divisors (1986571).

391315481 is a wasteful number, since it uses less digits than its factorization.

391315481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1986570.

The product of its digits is 12960, while the sum is 35.

The square root of 391315481 is about 19781.6956047756. The cubic root of 391315481 is about 731.4348964744.

The spelling of 391315481 in words is "three hundred ninety-one million, three hundred fifteen thousand, four hundred eighty-one".