1688649554 has 4 divisors (see below), whose sum is σ = 2532974334. Its totient is φ = 844324776.

The previous prime is 1688649553. The next prime is 1688649563. The reversal of 1688649554 is 4559468861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 4559468861 = 65099 ⋅70039.

It can be written as a sum of positive squares in only one way, i.e., 1544097025 + 144552529 = 39295^2 + 12023^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1688649554.

It is not an unprimeable number, because it can be changed into a prime (1688649551) 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 as a sum of consecutive naturals, namely, 422162387 + ... + 422162390.

Almost surely, 2^1688649554 is an apocalyptic number.

1688649554 is a deficient number, since it is larger than the sum of its proper divisors (844324780).

1688649554 is an equidigital number, since it uses as much as digits as its factorization.

1688649554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 844324779.

The product of its digits is 8294400, while the sum is 56.

The square root of 1688649554 is about 41093.1813565219. The cubic root of 1688649554 is about 1190.8210688314.

The spelling of 1688649554 in words is "one billion, six hundred eighty-eight million, six hundred forty-nine thousand, five hundred fifty-four".