1687221855 has 48 divisors (see below), whose sum is σ = 3193875360. Its totient is φ = 817152000.

The previous prime is 1687221853. The next prime is 1687221863. The reversal of 1687221855 is 5581227861.

It is not a de Polignac number, because 1687221855 - 2¹ = 1687221853 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 1687221855.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1687221853) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 791431 + ... + 793559.

It is an arithmetic number, because the mean of its divisors is an integer number (66539070).

Almost surely, 2^1687221855 is an apocalyptic number.

1687221855 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1687221855 is a deficient number, since it is larger than the sum of its proper divisors (1506653505).

1687221855 is a wasteful number, since it uses less digits than its factorization.

1687221855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3752 (or 3749 counting only the distinct ones).

The product of its digits is 268800, while the sum is 45.

The square root of 1687221855 is about 41075.8062002440. The cubic root of 1687221855 is about 1190.4853738760.

The spelling of 1687221855 in words is "one billion, six hundred eighty-seven million, two hundred twenty-one thousand, eight hundred fifty-five".