1687841820 has 384 divisors, whose sum is σ = 6425395200. Its totient is φ = 359251200.

The previous prime is 1687841819. The next prime is 1687841843. The reversal of 1687841820 is 281487861.

1687841820 is a `hidden beast` number, since 168 + 78 + 418 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 5099055 + ... + 5099385.

It is an arithmetic number, because the mean of its divisors is an integer number (16732800).

Almost surely, 2^1687841820 is an apocalyptic number.

1687841820 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 1687841820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3212697600).

1687841820 is an abundant number, since it is smaller than the sum of its proper divisors (4737553380).

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

1687841820 is a wasteful number, since it uses less digits than its factorization.

1687841820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446 (or 438 counting only the distinct ones).

The product of its (nonzero) digits is 172032, while the sum is 45.

The square root of 1687841820 is about 41083.3521027679. The cubic root of 1687841820 is about 1190.6311695384.

The spelling of 1687841820 in words is "one billion, six hundred eighty-seven million, eight hundred forty-one thousand, eight hundred twenty".