1688375405 has 4 divisors (see below), whose sum is σ = 2026050492. Its totient is φ = 1350700320.

The previous prime is 1688375399. The next prime is 1688375419. The reversal of 1688375405 is 5045738861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5045738861 = 1481 ⋅3406981.

It can be written as a sum of positive squares in 2 ways, for example, as 961372036 + 727003369 = 31006^2 + 26963^2 .

It is not a de Polignac number, because 1688375405 - 2²² = 1684181101 is a prime.

It is a super-2 number, since 2×1688375405² = 5701223016417828050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1688375405.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 168837536 + ... + 168837545.

It is an arithmetic number, because the mean of its divisors is an integer number (506512623).

Almost surely, 2^1688375405 is an apocalyptic number.

It is an amenable number.

1688375405 is a deficient number, since it is larger than the sum of its proper divisors (337675087).

1688375405 is an equidigital number, since it uses as much as digits as its factorization.

1688375405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 337675086.

The product of its (nonzero) digits is 806400, while the sum is 47.

The square root of 1688375405 is about 41089.8455217344. The cubic root of 1688375405 is about 1190.7566228421.

The spelling of 1688375405 in words is "one billion, six hundred eighty-eight million, three hundred seventy-five thousand, four hundred five".