391634 has 4 divisors (see below), whose sum is σ = 587454. Its totient is φ = 195816.

The previous prime is 391631. The next prime is 391639. The reversal of 391634 is 436193.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 436193 = 37 ⋅11789.

It can be written as a sum of positive squares in only one way, i.e., 330625 + 61009 = 575^2 + 247^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (391631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97907 + ... + 97910.

2³⁹¹⁶³⁴ is an apocalyptic number.

391634 is a deficient number, since it is larger than the sum of its proper divisors (195820).

391634 is a wasteful number, since it uses less digits than its factorization.

391634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195819.

The product of its digits is 1944, while the sum is 26.

The square root of 391634 is about 625.8066794147. The cubic root of 391634 is about 73.1633297969.

The spelling of 391634 in words is "three hundred ninety-one thousand, six hundred thirty-four".