671812878465 has 48 divisors (see below), whose sum is σ = 1165999536000. Its totient is φ = 357831694080.

The previous prime is 671812878449. The next prime is 671812878467. The reversal of 671812878465 is 564878218176.

It is a happy number.

671812878465 is a `hidden beast` number, since 6 + 7 + 1 + 81 + 28 + 78 + 465 = 666.

It is not a de Polignac number, because 671812878465 - 2⁴ = 671812878449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (671812878467) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 183003580 + ... + 183007250.

It is an arithmetic number, because the mean of its divisors is an integer number (24291657000).

Almost surely, 2^671812878465 is an apocalyptic number.

It is an amenable number.

671812878465 is a deficient number, since it is larger than the sum of its proper divisors (494186657535).

671812878465 is a wasteful number, since it uses less digits than its factorization.

671812878465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7894 (or 7891 counting only the distinct ones).

The product of its digits is 36126720, while the sum is 63.

The spelling of 671812878465 in words is "six hundred seventy-one billion, eight hundred twelve million, eight hundred seventy-eight thousand, four hundred sixty-five".