391973 has 4 divisors (see below), whose sum is σ = 393228. Its totient is φ = 390720.

The previous prime is 391967. The next prime is 391987. The reversal of 391973 is 379193.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 379193 = 59 ⋅6427.

It can be written as a sum of positive squares in 2 ways, for example, as 277729 + 114244 = 527^2 + 338^2 .

It is a cyclic number.

It is not a de Polignac number, because 391973 - 2⁸ = 391717 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 (391903) 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, 263 + ... + 923.

It is an arithmetic number, because the mean of its divisors is an integer number (98307).

2³⁹¹⁹⁷³ is an apocalyptic number.

It is an amenable number.

391973 is a deficient number, since it is larger than the sum of its proper divisors (1255).

391973 is an equidigital number, since it uses as much as digits as its factorization.

391973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1254.

The product of its digits is 5103, while the sum is 32.

The square root of 391973 is about 626.0774712446. The cubic root of 391973 is about 73.1844338684.

The spelling of 391973 in words is "three hundred ninety-one thousand, nine hundred seventy-three".