391855949 has 4 divisors (see below), whose sum is σ = 392067036. Its totient is φ = 391644864.

The previous prime is 391855931. The next prime is 391855951. The reversal of 391855949 is 949558193.

It is a happy number.

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 9653449 + 382202500 = 3107^2 + 19550^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-391855949 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 391855949.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391855909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102734 + ... + 106479.

It is an arithmetic number, because the mean of its divisors is an integer number (98016759).

Almost surely, 2^391855949 is an apocalyptic number.

It is an amenable number.

391855949 is a deficient number, since it is larger than the sum of its proper divisors (211087).

391855949 is a wasteful number, since it uses less digits than its factorization.

391855949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211086.

The product of its digits is 1749600, while the sum is 53.

The square root of 391855949 is about 19795.3517018516. The cubic root of 391855949 is about 731.7714836323.

The spelling of 391855949 in words is "three hundred ninety-one million, eight hundred fifty-five thousand, nine hundred forty-nine".