671409891 has 30 divisors (see below), whose sum is σ = 1028238156. Its totient is φ = 436600800.

The previous prime is 671409887. The next prime is 671409919. The reversal of 671409891 is 198904176.

It is a happy number.

It is not a de Polignac number, because 671409891 - 2² = 671409887 is a prime.

It is not an unprimeable number, because it can be changed into a prime (671409841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 133696 + ... + 138626.

Almost surely, 2^671409891 is an apocalyptic number.

671409891 is a deficient number, since it is larger than the sum of its proper divisors (356828265).

671409891 is an equidigital number, since it uses as much as digits as its factorization.

671409891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5025 (or 4975 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 671409891 is about 25911.5783193537. The cubic root of 671409891 is about 875.6473646329.

The spelling of 671409891 in words is "six hundred seventy-one million, four hundred nine thousand, eight hundred ninety-one".