1688666556 has 48 divisors (see below), whose sum is σ = 4009195008. Its totient is φ = 553089600.

The previous prime is 1688666543. The next prime is 1688666557. The reversal of 1688666556 is 6556668861.

It is a super-2 number, since 2×1688666556² = 5703189474705802272, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1688666496 and 1688666505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1688666557) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 261786 + ... + 268158.

It is an arithmetic number, because the mean of its divisors is an integer number (83524896).

Almost surely, 2^1688666556 is an apocalyptic number.

It is an amenable number.

1688666556 is an abundant number, since it is smaller than the sum of its proper divisors (2320528452).

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

1688666556 is a wasteful number, since it uses less digits than its factorization.

1688666556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6762 (or 6760 counting only the distinct ones).

The product of its digits is 12441600, while the sum is 57.

The square root of 1688666556 is about 41093.3882273049. The cubic root of 1688666556 is about 1190.8250653725.

The spelling of 1688666556 in words is "one billion, six hundred eighty-eight million, six hundred sixty-six thousand, five hundred fifty-six".