1681556836 has 12 divisors (see below), whose sum is σ = 3115826028. Its totient is φ = 791320832.

The previous prime is 1681556831. The next prime is 1681556837. The reversal of 1681556836 is 6386551861.

It can be written as a sum of positive squares in 2 ways, for example, as 515744100 + 1165812736 = 22710^2 + 34144^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1681556836.

It is not an unprimeable number, because it can be changed into a prime (1681556831) by changing a digit.

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, 12364321 + ... + 12364456.

It is an arithmetic number, because the mean of its divisors is an integer number (259652169).

Almost surely, 2^1681556836 is an apocalyptic number.

It is an amenable number.

1681556836 is a deficient number, since it is larger than the sum of its proper divisors (1434269192).

1681556836 is a wasteful number, since it uses less digits than its factorization.

1681556836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24728798 (or 24728796 counting only the distinct ones).

The product of its digits is 1036800, while the sum is 49.

The square root of 1681556836 is about 41006.7901206617. The cubic root of 1681556836 is about 1189.1514879619.

It can be divided in two parts, 16815 and 56836, that multiplied together give a triangular number (955697340 = T₄₃₇₁₉).

The spelling of 1681556836 in words is "one billion, six hundred eighty-one million, five hundred fifty-six thousand, eight hundred thirty-six".