10661555404800 has 1224 divisors, whose sum is σ = 40347260873920. Its totient is φ = 2790103449600.

The previous prime is 10661555404751. The next prime is 10661555404879. The reversal of 10661555404800 is 840455516601.

10661555404800 is a `hidden beast` number, since 1 + 0 + 6 + 6 + 15 + 554 + 0 + 4 + 80 + 0 = 666.

It is a super-2 number, since 2×10661555404800² (a number of 27 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 24286002981 + ... + 24286003419.

Almost surely, 2^{10661555404800} is an apocalyptic number.

10661555404800 is a gapful number since it is divisible by the number (10) 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 10661555404800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20173630436960).

10661555404800 is an abundant number, since it is smaller than the sum of its proper divisors (29685705469120).

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

10661555404800 is an frugal number, since it uses more digits than its factorization.

10661555404800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 557 (or 510 counting only the distinct ones).

The product of its (nonzero) digits is 576000, while the sum is 45.

The spelling of 10661555404800 in words is "ten trillion, six hundred sixty-one billion, five hundred fifty-five million, four hundred four thousand, eight hundred".