20661141242880 has 704 divisors, whose sum is σ = 74605403496960. Its totient is φ = 5421809664000.

The previous prime is 20661141242851. The next prime is 20661141242939. The reversal of 20661141242880 is 8824214116602.

20661141242880 is a `hidden beast` number, since 2 + 0 + 6 + 6 + 1 + 141 + 2 + 428 + 80 = 666.

It is a super-2 number, since 2×20661141242880² (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 pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2331689650 + ... + 2331698510.

Almost surely, 2^{20661141242880} is an apocalyptic number.

20661141242880 is a gapful number since it is divisible by the number (20) 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 20661141242880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37302701748480).

20661141242880 is an abundant number, since it is smaller than the sum of its proper divisors (53944262254080).

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

20661141242880 is a wasteful number, since it uses less digits than its factorization.

20661141242880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9163 (or 9139 counting only the distinct ones).

The product of its (nonzero) digits is 294912, while the sum is 45.

The spelling of 20661141242880 in words is "twenty trillion, six hundred sixty-one billion, one hundred forty-one million, two hundred forty-two thousand, eight hundred eighty".