661214181888 has 960 divisors, whose sum is σ = 2233338307200. Its totient is φ = 195124101120.

The previous prime is 661214181833. The next prime is 661214181889. The reversal of 661214181888 is 888181412166.

661214181888 is a `hidden beast` number, since 6 + 612 + 1 + 4 + 1 + 8 + 18 + 8 + 8 = 666.

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

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (661214181889) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 11207020003 + ... + 11207020061.

It is an arithmetic number, because the mean of its divisors is an integer number (2326394070).

Almost surely, 2^661214181888 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 661214181888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1116669153600).

661214181888 is an abundant number, since it is smaller than the sum of its proper divisors (1572124125312).

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

661214181888 is an frugal number, since it uses more digits than its factorization.

661214181888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172 (or 118 counting only the distinct ones).

The product of its digits is 1179648, while the sum is 54.

The spelling of 661214181888 in words is "six hundred sixty-one billion, two hundred fourteen million, one hundred eighty-one thousand, eight hundred eighty-eight".