61581578880 has 256 divisors, whose sum is σ = 206400182400. Its totient is φ = 15594700800.

The previous prime is 61581578857. The next prime is 61581578951. The reversal of 61581578880 is 8887518516.

It is a self number, because there is not a number n which added to its sum of digits gives 61581578880.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3387415 + ... + 3405545.

Almost surely, 2^61581578880 is an apocalyptic number.

61581578880 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 61581578880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103200091200).

61581578880 is an abundant number, since it is smaller than the sum of its proper divisors (144818603520).

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

61581578880 is a wasteful number, since it uses less digits than its factorization.

61581578880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18243 (or 18231 counting only the distinct ones).

The product of its (nonzero) digits is 4300800, while the sum is 57.

The spelling of 61581578880 in words is "sixty-one billion, five hundred eighty-one million, five hundred seventy-eight thousand, eight hundred eighty".