671660115721 has 16 divisors (see below), whose sum is σ = 801074098944. Its totient is φ = 550617274944.

The previous prime is 671660115683. The next prime is 671660115743. The reversal of 671660115721 is 127511066176.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 671660115721 - 2⁹ = 671660115209 is a prime.

It is a super-2 number, since 2×671660115721² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (671660115761) 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 15 ways as a sum of consecutive naturals, for example, 1268751 + ... + 1718443.

It is an arithmetic number, because the mean of its divisors is an integer number (50067131184).

Almost surely, 2^671660115721 is an apocalyptic number.

It is an amenable number.

671660115721 is a deficient number, since it is larger than the sum of its proper divisors (129413983223).

671660115721 is a wasteful number, since it uses less digits than its factorization.

671660115721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 459000.

The product of its (nonzero) digits is 105840, while the sum is 43.

The spelling of 671660115721 in words is "six hundred seventy-one billion, six hundred sixty million, one hundred fifteen thousand, seven hundred twenty-one".