61666620304644 has 192 divisors, whose sum is σ = 163577489644800. Its totient is φ = 20084011370496.

The previous prime is 61666620304631. The next prime is 61666620304697. The reversal of 61666620304644 is 44640302666616.

61666620304644 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4582487164 + ... + 4582500620.

It is an arithmetic number, because the mean of its divisors is an integer number (851966091900).

Almost surely, 2^{61666620304644} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61666620304644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81788744822400).

61666620304644 is an abundant number, since it is smaller than the sum of its proper divisors (101910869340156).

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

61666620304644 is a wasteful number, since it uses less digits than its factorization.

61666620304644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17859 (or 17851 counting only the distinct ones).

The product of its (nonzero) digits is 17915904, while the sum is 54.

The spelling of 61666620304644 in words is "sixty-one trillion, six hundred sixty-six billion, six hundred twenty million, three hundred four thousand, six hundred forty-four".