161998888550400 has 5040 divisors, whose sum is σ = 712830107286528. Its totient is φ = 36118462464000.

The previous prime is 161998888550383. The next prime is 161998888550419. The reversal of 161998888550400 is 4055888899161.

161998888550400 is a `hidden beast` number, since 1 + 6 + 1 + 9 + 98 + 8 + 8 + 85 + 50 + 400 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

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 335 ways as a sum of consecutive naturals, for example, 3767416012779 + ... + 3767416012821.

Almost surely, 2^{161998888550400} is an apocalyptic number.

161998888550400 is a gapful number since it is divisible by the number (10) 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 161998888550400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (356415053643264).

161998888550400 is an abundant number, since it is smaller than the sum of its proper divisors (550831218736128).

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

161998888550400 is an equidigital number, since it uses as much as digits as its factorization.

161998888550400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178 (or 132 counting only the distinct ones).

The product of its (nonzero) digits is 199065600, while the sum is 72.

The spelling of 161998888550400 in words is "one hundred sixty-one trillion, nine hundred ninety-eight billion, eight hundred eighty-eight million, five hundred fifty thousand, four hundred".