1689961988 has 72 divisors (see below), whose sum is σ = 3515582616. Its totient is φ = 706083840.

The previous prime is 1689961981. The next prime is 1689961991. The reversal of 1689961988 is 8891699861.

It can be written as a sum of positive squares in 4 ways, for example, as 8305924 + 1681656064 = 2882^2 + 41008^2 .

It is not an unprimeable number, because it can be changed into a prime (1689961981) 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 23 ways as a sum of consecutive naturals, for example, 2120006 + ... + 2120802.

Almost surely, 2^1689961988 is an apocalyptic number.

It is an amenable number.

1689961988 is an abundant number, since it is smaller than the sum of its proper divisors (1825620628).

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

1689961988 is a wasteful number, since it uses less digits than its factorization.

1689961988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1173 (or 1160 counting only the distinct ones).

The product of its digits is 13436928, while the sum is 65.

The square root of 1689961988 is about 41109.1472545953. The cubic root of 1689961988 is about 1191.1294946455.

It can be divided in two parts, 16899 and 61988, that added together give a palindrome (78887).

The spelling of 1689961988 in words is "one billion, six hundred eighty-nine million, nine hundred sixty-one thousand, nine hundred eighty-eight".