681993984 has 72 divisors (see below), whose sum is σ = 2074414720. Its totient is φ = 194853888.

The previous prime is 681993971. The next prime is 681993997. The reversal of 681993984 is 489399186.

It is an interprime number because it is at equal distance from previous prime (681993971) and next prime (681993997).

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58054 + ... + 68805.

Almost surely, 2^681993984 is an apocalyptic number.

681993984 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

681993984 is an abundant number, since it is smaller than the sum of its proper divisors (1392420736).

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

681993984 is a wasteful number, since it uses less digits than its factorization.

681993984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126885 (or 126871 counting only the distinct ones).

The product of its digits is 3359232, while the sum is 57.

The square root of 681993984 is about 26115.0145318742. The cubic root of 681993984 is about 880.2246258535.

The spelling of 681993984 in words is "six hundred eighty-one million, nine hundred ninety-three thousand, nine hundred eighty-four".