161805975552 has 540 divisors, whose sum is σ = 521347610784. Its totient is φ = 48306585600.

The previous prime is 161805975533. The next prime is 161805975593. The reversal of 161805975552 is 255579508161.

161805975552 is a `hidden beast` number, since 1 + 6 + 1 + 80 + 5 + 9 + 7 + 5 + 552 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1071562677 + ... + 1071562827.

Almost surely, 2^161805975552 is an apocalyptic number.

161805975552 is a gapful number since it is divisible by the number (12) 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 161805975552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (260673805392).

161805975552 is an abundant number, since it is smaller than the sum of its proper divisors (359541635232).

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

161805975552 is a wasteful number, since it uses less digits than its factorization.

161805975552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254 (or 212 counting only the distinct ones).

The product of its (nonzero) digits is 3780000, while the sum is 54.

The spelling of 161805975552 in words is "one hundred sixty-one billion, eight hundred five million, nine hundred seventy-five thousand, five hundred fifty-two".