671878381 has 2 divisors, whose sum is σ = 671878382. Its totient is φ = 671878380.

The previous prime is 671878379. The next prime is 671878391. The reversal of 671878381 is 183878176.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 401802025 + 270076356 = 20045^2 + 16434^2 .

It is a cyclic number.

It is not a de Polignac number, because 671878381 - 2¹ = 671878379 is a prime.

It is a super-2 number, since 2×671878381² = 902841117710362322, which contains 22 as substring.

Together with 671878379, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671878391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335939190 + 335939191.

It is an arithmetic number, because the mean of its divisors is an integer number (335939191).

Almost surely, 2^671878381 is an apocalyptic number.

It is an amenable number.

671878381 is a deficient number, since it is larger than the sum of its proper divisors (1).

671878381 is an equidigital number, since it uses as much as digits as its factorization.

671878381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 451584, while the sum is 49.

The square root of 671878381 is about 25920.6169100969. The cubic root of 671878381 is about 875.8509842401.

The spelling of 671878381 in words is "six hundred seventy-one million, eight hundred seventy-eight thousand, three hundred eighty-one".