391861369 has 4 divisors (see below), whose sum is σ = 405373860. Its totient is φ = 378348880.

The previous prime is 391861363. The next prime is 391861391. The reversal of 391861369 is 963168193.

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 263900025 + 127961344 = 16245^2 + 11312^2 .

It is a cyclic number.

It is not a de Polignac number, because 391861369 - 2³ = 391861361 is a prime.

It is a super-2 number, since 2×391861369² = 307110665029108322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391861361) 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 3 ways as a sum of consecutive naturals, for example, 6756202 + ... + 6756259.

It is an arithmetic number, because the mean of its divisors is an integer number (101343465).

Almost surely, 2^391861369 is an apocalyptic number.

It is an amenable number.

391861369 is a deficient number, since it is larger than the sum of its proper divisors (13512491).

391861369 is a wasteful number, since it uses less digits than its factorization.

391861369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13512490.

The product of its digits is 209952, while the sum is 46.

The square root of 391861369 is about 19795.4886022043. The cubic root of 391861369 is about 731.7748574768.

The spelling of 391861369 in words is "three hundred ninety-one million, eight hundred sixty-one thousand, three hundred sixty-nine".