671221939 has 2 divisors, whose sum is σ = 671221940. Its totient is φ = 671221938.

The previous prime is 671221871. The next prime is 671221963. The reversal of 671221939 is 939122176.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 671221939 - 2¹⁵ = 671189171 is a prime.

It is equal to p_34838626 and since 671221939 and 34838626 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (671221039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335610969 + 335610970.

It is an arithmetic number, because the mean of its divisors is an integer number (335610970).

Almost surely, 2^671221939 is an apocalyptic number.

671221939 is a deficient number, since it is larger than the sum of its proper divisors (1).

671221939 is an equidigital number, since it uses as much as digits as its factorization.

671221939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40824, while the sum is 40.

The square root of 671221939 is about 25907.9512698322. The cubic root of 671221939 is about 875.5656485131.

The spelling of 671221939 in words is "six hundred seventy-one million, two hundred twenty-one thousand, nine hundred thirty-nine".