1681288821 has 24 divisors (see below), whose sum is σ = 2467774400. Its totient is φ = 1102787136.

The previous prime is 1681288811. The next prime is 1681288837. The reversal of 1681288821 is 1288821861.

It is not a de Polignac number, because 1681288821 - 2⁵ = 1681288789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681288811) 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 in 23 ways as a sum of consecutive naturals, for example, 842601 + ... + 844593.

Almost surely, 2^1681288821 is an apocalyptic number.

It is an amenable number.

1681288821 is a deficient number, since it is larger than the sum of its proper divisors (786485579).

1681288821 is a wasteful number, since it uses less digits than its factorization.

1681288821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3465 (or 3462 counting only the distinct ones).

The product of its digits is 98304, while the sum is 45.

The square root of 1681288821 is about 41003.5220560381. The cubic root of 1681288821 is about 1189.0883069534.

The spelling of 1681288821 in words is "one billion, six hundred eighty-one million, two hundred eighty-eight thousand, eight hundred twenty-one".