1381687081668 has 18 divisors (see below), whose sum is σ = 3492597900974. Its totient is φ = 460562360544.

The previous prime is 1381687081657. The next prime is 1381687081673. The reversal of 1381687081668 is 8661807861831.

It can be written as a sum of positive squares in only one way, i.e., 1069337991744 + 312349089924 = 1034088^2 + 558882^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19190098321 + ... + 19190098392.

Almost surely, 2^{1381687081668} is an apocalyptic number.

1381687081668 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1381687081668 is an abundant number, since it is smaller than the sum of its proper divisors (2110910819306).

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

1381687081668 is a wasteful number, since it uses less digits than its factorization.

1381687081668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38380196723 (or 38380196718 counting only the distinct ones).

The product of its (nonzero) digits is 18579456, while the sum is 63.

It can be divided in two parts, 138168708 and 1668, that added together give a triangular number (138170376 = T₁₆₆₂₃).

The spelling of 1381687081668 in words is "one trillion, three hundred eighty-one billion, six hundred eighty-seven million, eighty-one thousand, six hundred sixty-eight".