161921894421600 has 1440 divisors, whose sum is σ = 617769149681376. Its totient is φ = 41231661465600.

The previous prime is 161921894421593. The next prime is 161921894421607. The reversal of 161921894421600 is 6124498129161.

161921894421600 is a `hidden beast` number, since 1 + 6 + 1 + 9 + 2 + 1 + 8 + 9 + 4 + 4 + 21 + 600 = 666.

It is an interprime number because it is at equal distance from previous prime (161921894421593) and next prime (161921894421607).

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 (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161921894421607) by changing a digit.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 86728383867 + ... + 86728385733.

Almost surely, 2^{161921894421600} is an apocalyptic number.

161921894421600 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 161921894421600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (308884574840688).

161921894421600 is an abundant number, since it is smaller than the sum of its proper divisors (455847255259776).

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

161921894421600 is a wasteful number, since it uses less digits than its factorization.

161921894421600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2590 (or 2568 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 54.

The spelling of 161921894421600 in words is "one hundred sixty-one trillion, nine hundred twenty-one billion, eight hundred ninety-four million, four hundred twenty-one thousand, six hundred".