161387550 has 144 divisors (see below), whose sum is σ = 467970048. Its totient is φ = 39758400.

The previous prime is 161387549. The next prime is 161387561. The reversal of 161387550 is 55783161.

161387550 is a `hidden beast` number, since 16 + 13 + 87 + 550 = 666.

161387550 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 320599 + ... + 321101.

It is an arithmetic number, because the mean of its divisors is an integer number (3249792).

Almost surely, 2^161387550 is an apocalyptic number.

161387550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 161387550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (233985024).

161387550 is an abundant number, since it is smaller than the sum of its proper divisors (306582498).

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

161387550 is a wasteful number, since it uses less digits than its factorization.

161387550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 575 (or 567 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The square root of 161387550 is about 12703.8399706545. The cubic root of 161387550 is about 544.4483377789.

The spelling of 161387550 in words is "one hundred sixty-one million, three hundred eighty-seven thousand, five hundred fifty".