161788500 has 144 divisors (see below), whose sum is σ = 515882640. Its totient is φ = 42681600.

The previous prime is 161788499. The next prime is 161788519. The reversal of 161788500 is 5887161.

It can be written as a sum of positive squares in 8 ways, for example, as 30869136 + 130919364 = 5556^2 + 11442^2 .

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 706386 + ... + 706614.

Almost surely, 2^161788500 is an apocalyptic number.

161788500 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 161788500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (257941320).

161788500 is an abundant number, since it is smaller than the sum of its proper divisors (354094140).

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

161788500 is a wasteful number, since it uses less digits than its factorization.

161788500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411 (or 396 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 36.

The square root of 161788500 is about 12719.6108431037. The cubic root of 161788500 is about 544.8988393449.

The spelling of 161788500 in words is "one hundred sixty-one million, seven hundred eighty-eight thousand, five hundred".