1686778071840 has 480 divisors, whose sum is σ = 6312362120064. Its totient is φ = 422725754880.

The previous prime is 1686778071829. The next prime is 1686778071841. The reversal of 1686778071840 is 481708776861.

It is a tau number, because it is divible by the number of its divisors (480).

It is not an unprimeable number, because it can be changed into a prime (1686778071841) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 160167375 + ... + 160177905.

Almost surely, 2^{1686778071840} is an apocalyptic number.

1686778071840 is a gapful number since it is divisible by the number (10) 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 1686778071840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3156181060032).

1686778071840 is an abundant number, since it is smaller than the sum of its proper divisors (4625584048224).

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

1686778071840 is a wasteful number, since it uses less digits than its factorization.

1686778071840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11302 (or 11285 counting only the distinct ones).

The product of its (nonzero) digits is 25288704, while the sum is 63.

The spelling of 1686778071840 in words is "one trillion, six hundred eighty-six billion, seven hundred seventy-eight million, seventy-one thousand, eight hundred forty".