681963840 has 224 divisors, whose sum is σ = 2547884160. Its totient is φ = 171122688.

The previous prime is 681963829. The next prime is 681963851. The reversal of 681963840 is 48369186.

681963840 is a `hidden beast` number, since 6 + 8 + 1 + 9 + 638 + 4 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (681963829) and next prime (681963851).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 144559 + ... + 149201.

Almost surely, 2^681963840 is an apocalyptic number.

681963840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 681963840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1273942080).

681963840 is an abundant number, since it is smaller than the sum of its proper divisors (1865920320).

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

681963840 is a wasteful number, since it uses less digits than its factorization.

681963840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4686 (or 4670 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 681963840 is about 26114.4373862429. The cubic root of 681963840 is about 880.2116570773.

The spelling of 681963840 in words is "six hundred eighty-one million, nine hundred sixty-three thousand, eight hundred forty".