161891200800 has 1440 divisors, whose sum is σ = 722323768320. Its totient is φ = 34488115200.

The previous prime is 161891200777. The next prime is 161891200819. The reversal of 161891200800 is 8002198161.

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 407786202 + ... + 407786598.

It is an arithmetic number, because the mean of its divisors is an integer number (501613728).

Almost surely, 2^161891200800 is an apocalyptic number.

161891200800 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 161891200800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (361161884160).

161891200800 is an abundant number, since it is smaller than the sum of its proper divisors (560432567520).

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

161891200800 is a wasteful number, since it uses less digits than its factorization.

161891200800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 496 (or 474 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 36.

Adding to 161891200800 its reverse (8002198161), we get a palindrome (169893398961).

The spelling of 161891200800 in words is "one hundred sixty-one billion, eight hundred ninety-one million, two hundred thousand, eight hundred".