1687860655821 has 16 divisors (see below), whose sum is σ = 2632141374400. Its totient is φ = 1066017255984.

The previous prime is 1687860655781. The next prime is 1687860655847. The reversal of 1687860655821 is 1285560687861.

1687860655821 is a `hidden beast` number, since 1 + 6 + 8 + 78 + 6 + 0 + 6 + 558 + 2 + 1 = 666.

It is not a de Polignac number, because 1687860655821 - 2¹⁸ = 1687860393677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1687860655891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1645087846 + ... + 1645088871.

It is an arithmetic number, because the mean of its divisors is an integer number (164508835900).

Almost surely, 2^{1687860655821} is an apocalyptic number.

It is an amenable number.

1687860655821 is a deficient number, since it is larger than the sum of its proper divisors (944280718579).

1687860655821 is a wasteful number, since it uses less digits than its factorization.

1687860655821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3290176745 (or 3290176739 counting only the distinct ones).

The product of its (nonzero) digits is 38707200, while the sum is 63.

The spelling of 1687860655821 in words is "one trillion, six hundred eighty-seven billion, eight hundred sixty million, six hundred fifty-five thousand, eight hundred twenty-one".