661588058880 has 1728 divisors, whose sum is σ = 2943383546880. Its totient is φ = 140200574976.

The previous prime is 661588058851. The next prime is 661588058891. The reversal of 661588058880 is 88850885166.

661588058880 is a `hidden beast` number, since 6 + 615 + 8 + 8 + 0 + 5 + 8 + 8 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1728).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 9874448607 + ... + 9874448673.

It is an arithmetic number, because the mean of its divisors is an integer number (1703346960).

Almost surely, 2^661588058880 is an apocalyptic number.

661588058880 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 661588058880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1471691773440).

661588058880 is an abundant number, since it is smaller than the sum of its proper divisors (2281795488000).

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

661588058880 is an frugal number, since it uses more digits than its factorization.

661588058880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 29491200, while the sum is 63.

The spelling of 661588058880 in words is "six hundred sixty-one billion, five hundred eighty-eight million, fifty-eight thousand, eight hundred eighty".