1687890721920 has 512 divisors, whose sum is σ = 5959593722880. Its totient is φ = 403641335808.

The previous prime is 1687890721879. The next prime is 1687890721931. The reversal of 1687890721920 is 291270987861.

It is a Smith number, since the sum of its digits (60) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1018641732 + ... + 1018643388.

It is an arithmetic number, because the mean of its divisors is an integer number (11639831490).

Almost surely, 2^{1687890721920} is an apocalyptic number.

1687890721920 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 1687890721920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2979796861440).

1687890721920 is an abundant number, since it is smaller than the sum of its proper divisors (4271703000960).

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

1687890721920 is a wasteful number, since it uses less digits than its factorization.

1687890721920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2832 (or 2820 counting only the distinct ones).

The product of its (nonzero) digits is 6096384, while the sum is 60.

The spelling of 1687890721920 in words is "one trillion, six hundred eighty-seven billion, eight hundred ninety million, seven hundred twenty-one thousand, nine hundred twenty".