681540980225544 has 80 divisors (see below), whose sum is σ = 1910178176923500. Its totient is φ = 227033663833728.

The previous prime is 681540980225543. The next prime is 681540980225587. The reversal of 681540980225544 is 445522089045186.

681540980225544 is a `hidden beast` number, since 6 + 8 + 1 + 5 + 4 + 0 + 9 + 80 + 2 + 2 + 5 + 544 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 610684822113444 + 70856158112100 = 24712038^2 + 8417610^2 .

It is a super-2 number, since 2×681540980225544² (a number of 30 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (681540980225543) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 338492947 + ... + 340500450.

Almost surely, 2^{681540980225544} is an apocalyptic number.

It is an amenable number.

681540980225544 is an abundant number, since it is smaller than the sum of its proper divisors (1228637196697956).

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

681540980225544 is a wasteful number, since it uses less digits than its factorization.

681540980225544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 678994964 (or 678994951 counting only the distinct ones).

The product of its (nonzero) digits is 110592000, while the sum is 63.

The spelling of 681540980225544 in words is "six hundred eighty-one trillion, five hundred forty billion, nine hundred eighty million, two hundred twenty-five thousand, five hundred forty-four".