661724477740800 has 1080 divisors, whose sum is σ = 2498106208219776. Its totient is φ = 172783741870080.

The previous prime is 661724477740783. The next prime is 661724477740801. The reversal of 661724477740800 is 8047774427166.

661724477740800 is a `hidden beast` number, since 6 + 6 + 1 + 7 + 2 + 447 + 77 + 40 + 80 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1080).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661724477740801) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 5800320559 + ... + 5800434641.

Almost surely, 2^{661724477740800} is an apocalyptic number.

661724477740800 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 661724477740800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1249053104109888).

661724477740800 is an abundant number, since it is smaller than the sum of its proper divisors (1836381730478976).

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

661724477740800 is a wasteful number, since it uses less digits than its factorization.

661724477740800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114355 (or 114327 counting only the distinct ones).

The product of its (nonzero) digits is 88510464, while the sum is 63.

The spelling of 661724477740800 in words is "six hundred sixty-one trillion, seven hundred twenty-four billion, four hundred seventy-seven million, seven hundred forty thousand, eight hundred".