681126512640 has 384 divisors, whose sum is σ = 2495827676160. Its totient is φ = 155344896000.

The previous prime is 681126512593. The next prime is 681126512641. The reversal of 681126512640 is 46215621186.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-2 number, since 2×681126512640² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 681126512592 and 681126512601.

It is not an unprimeable number, because it can be changed into a prime (681126512641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 105581415 + ... + 105587865.

It is an arithmetic number, because the mean of its divisors is an integer number (6499551240).

Almost surely, 2^681126512640 is an apocalyptic number.

681126512640 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 681126512640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1247913838080).

681126512640 is an abundant number, since it is smaller than the sum of its proper divisors (1814701163520).

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

681126512640 is a wasteful number, since it uses less digits than its factorization.

681126512640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6979 (or 6959 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 42.

The spelling of 681126512640 in words is "six hundred eighty-one billion, one hundred twenty-six million, five hundred twelve thousand, six hundred forty".