61566133720 has 256 divisors, whose sum is σ = 175677465600. Its totient is φ = 18895472640.

The previous prime is 61566133711. The next prime is 61566133721. The reversal of 61566133720 is 2733166516.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61566133721) by changing a digit.

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, 56430375 + ... + 56431465.

It is an arithmetic number, because the mean of its divisors is an integer number (686240100).

Almost surely, 2^61566133720 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 61566133720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87838732800).

61566133720 is an abundant number, since it is smaller than the sum of its proper divisors (114111331880).

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

61566133720 is a wasteful number, since it uses less digits than its factorization.

61566133720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1578 (or 1574 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 40.

The spelling of 61566133720 in words is "sixty-one billion, five hundred sixty-six million, one hundred thirty-three thousand, seven hundred twenty".