681864335640 has 48 divisors (see below), whose sum is σ = 2216059092000. Its totient is φ = 181830489408.

The previous prime is 681864335639. The next prime is 681864335653. The reversal of 681864335640 is 46533468186.

681864335640 is a `hidden beast` number, since 6 + 8 + 18 + 64 + 3 + 3 + 564 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 947033440 + ... + 947034159.

It is an arithmetic number, because the mean of its divisors is an integer number (46167897750).

Almost surely, 2^681864335640 is an apocalyptic number.

681864335640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

681864335640 is an abundant number, since it is smaller than the sum of its proper divisors (1534194756360).

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

681864335640 is a wasteful number, since it uses less digits than its factorization.

681864335640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1894067616 (or 1894067609 counting only the distinct ones).

The product of its (nonzero) digits is 9953280, while the sum is 54.

The spelling of 681864335640 in words is "six hundred eighty-one billion, eight hundred sixty-four million, three hundred thirty-five thousand, six hundred forty".