671861135947680 has 4032 divisors, whose sum is σ = 3040417023694848. Its totient is φ = 137154128117760.

The previous prime is 671861135947633. The next prime is 671861135947721. The reversal of 671861135947680 is 86749531168176.

671861135947680 is a `hidden beast` number, since 6 + 7 + 1 + 8 + 61 + 13 + 5 + 9 + 476 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 671861135947599 and 671861135947608.

It is an unprimeable number.

It is a polite number, since it can be written in 671 ways as a sum of consecutive naturals, for example, 387686748094 + ... + 387686749826.

It is an arithmetic number, because the mean of its divisors is an integer number (754071682464).

Almost surely, 2^{671861135947680} is an apocalyptic number.

671861135947680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 671861135947680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1520208511847424).

671861135947680 is an abundant number, since it is smaller than the sum of its proper divisors (2368555887747168).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

671861135947680 is a wasteful number, since it uses less digits than its factorization.

671861135947680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1891 (or 1851 counting only the distinct ones).

The product of its (nonzero) digits is 365783040, while the sum is 72.

The spelling of 671861135947680 in words is "six hundred seventy-one trillion, eight hundred sixty-one billion, one hundred thirty-five million, nine hundred forty-seven thousand, six hundred eighty".