391045 has 8 divisors (see below), whose sum is σ = 472824. Its totient is φ = 310464.

The previous prime is 391031. The next prime is 391049. The reversal of 391045 is 540193.

It can be written as a sum of positive squares in 4 ways, for example, as 173889 + 217156 = 417^2 + 466^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 391045 - 2¹⁵ = 358277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391049) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 787 + ... + 1183.

It is an arithmetic number, because the mean of its divisors is an integer number (59103).

2³⁹¹⁰⁴⁵ is an apocalyptic number.

It is an amenable number.

391045 is a deficient number, since it is larger than the sum of its proper divisors (81779).

391045 is a wasteful number, since it uses less digits than its factorization.

391045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 391045 is about 625.3359097317. The cubic root of 391045 is about 73.1266332701.

It can be divided in two parts, 39 and 1045, that multiplied together give a triangular number (40755 = T₂₈₅).

The spelling of 391045 in words is "three hundred ninety-one thousand, forty-five".