391315381 has 4 divisors (see below), whose sum is σ = 392207200. Its totient is φ = 390423564.

The previous prime is 391315349. The next prime is 391315411. The reversal of 391315381 is 183513193.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 391315381 - 2⁵ = 391315349 is a prime.

It is a super-2 number, since 2×391315381² = 306255454814350322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391355381) 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, 445251 + ... + 446128.

It is an arithmetic number, because the mean of its divisors is an integer number (98051800).

Almost surely, 2^391315381 is an apocalyptic number.

It is an amenable number.

391315381 is a deficient number, since it is larger than the sum of its proper divisors (891819).

391315381 is an equidigital number, since it uses as much as digits as its factorization.

391315381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891818.

The product of its digits is 9720, while the sum is 34.

The square root of 391315381 is about 19781.6930771863. The cubic root of 391315381 is about 731.4348341687.

The spelling of 391315381 in words is "three hundred ninety-one million, three hundred fifteen thousand, three hundred eighty-one".