671905 has 8 divisors (see below), whose sum is σ = 868392. Its totient is φ = 496128.

The previous prime is 671903. The next prime is 671911. The reversal of 671905 is 509176.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 17424 + 654481 = 132^2 + 809^2 .

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 671905 - 2¹ = 671903 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (671903) 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, 5104 + ... + 5233.

It is an arithmetic number, because the mean of its divisors is an integer number (108549).

2⁶⁷¹⁹⁰⁵ is an apocalyptic number.

671905 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

671905 is a deficient number, since it is larger than the sum of its proper divisors (196487).

671905 is a wasteful number, since it uses less digits than its factorization.

671905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10355.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 671905 is about 819.6981151619. The cubic root of 671905 is about 87.5862550802.

The spelling of 671905 in words is "six hundred seventy-one thousand, nine hundred five".