861578055888 has 80 divisors (see below), whose sum is σ = 2430373678272. Its totient is φ = 260838016000.

The previous prime is 861578055883. The next prime is 861578055889. The reversal of 861578055888 is 888550875168.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861578055883) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 208773 + ... + 1329188.

Almost surely, 2^861578055888 is an apocalyptic number.

861578055888 is a gapful number since it is divisible by the number (88) 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 861578055888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1215186839136).

861578055888 is an abundant number, since it is smaller than the sum of its proper divisors (1568795622384).

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

861578055888 is a wasteful number, since it uses less digits than its factorization.

861578055888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1539044 (or 1539038 counting only the distinct ones).

The product of its (nonzero) digits is 172032000, while the sum is 69.

The spelling of 861578055888 in words is "eight hundred sixty-one billion, five hundred seventy-eight million, fifty-five thousand, eight hundred eighty-eight".