671721373 has 4 divisors (see below), whose sum is σ = 671841180. Its totient is φ = 671601568.

The previous prime is 671721331. The next prime is 671721377. The reversal of 671721373 is 373127176.

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 263802564 + 407918809 = 16242^2 + 20197^2 .

It is a cyclic number.

It is not a de Polignac number, because 671721373 - 2²⁵ = 638166941 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 (671721377) 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, 51058 + ... + 62851.

It is an arithmetic number, because the mean of its divisors is an integer number (167960295).

Almost surely, 2^671721373 is an apocalyptic number.

It is an amenable number.

671721373 is a deficient number, since it is larger than the sum of its proper divisors (119807).

671721373 is a wasteful number, since it uses less digits than its factorization.

671721373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119806.

The product of its digits is 37044, while the sum is 37.

The square root of 671721373 is about 25917.5881015190. The cubic root of 671721373 is about 875.7827544690.

It can be divided in two parts, 67 and 1721373, that added together give a triangular number (1721440 = T₁₈₅₅).

The spelling of 671721373 in words is "six hundred seventy-one million, seven hundred twenty-one thousand, three hundred seventy-three".