671863121 has 2 divisors, whose sum is σ = 671863122. Its totient is φ = 671863120.

The previous prime is 671863117. The next prime is 671863141. The reversal of 671863121 is 121368176.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 667705600 + 4157521 = 25840^2 + 2039^2 .

It is a cyclic number.

It is not a de Polignac number, because 671863121 - 2² = 671863117 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (671863111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335931560 + 335931561.

It is an arithmetic number, because the mean of its divisors is an integer number (335931561).

Almost surely, 2^671863121 is an apocalyptic number.

It is an amenable number.

671863121 is a deficient number, since it is larger than the sum of its proper divisors (1).

671863121 is an equidigital number, since it uses as much as digits as its factorization.

671863121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 35.

The square root of 671863121 is about 25920.3225481474. The cubic root of 671863121 is about 875.8443532845.

It can be divided in two parts, 67186 and 3121, that added together give a palindrome (70307).

The spelling of 671863121 in words is "six hundred seventy-one million, eight hundred sixty-three thousand, one hundred twenty-one".