1689868521 has 16 divisors (see below), whose sum is σ = 2731101120. Its totient is φ = 1024162560.

The previous prime is 1689868519. The next prime is 1689868549. The reversal of 1689868521 is 1258689861.

It is a happy number.

It is not a de Polignac number, because 1689868521 - 2¹ = 1689868519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1689868321) 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, 2844600 + ... + 2845193.

It is an arithmetic number, because the mean of its divisors is an integer number (170693820).

Almost surely, 2^1689868521 is an apocalyptic number.

1689868521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1689868521 is a deficient number, since it is larger than the sum of its proper divisors (1041232599).

1689868521 is a wasteful number, since it uses less digits than its factorization.

1689868521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5689813 (or 5689807 counting only the distinct ones).

The product of its digits is 1658880, while the sum is 54.

The square root of 1689868521 is about 41108.0104237605. The cubic root of 1689868521 is about 1191.1075349103.

It can be divided in two parts, 168 and 9868521, that added together give a palindrome (9868689).

The spelling of 1689868521 in words is "one billion, six hundred eighty-nine million, eight hundred sixty-eight thousand, five hundred twenty-one".