161155800 has 288 divisors, whose sum is σ = 597149280. Its totient is φ = 38707200.

The previous prime is 161155781. The next prime is 161155811. The reversal of 161155800 is 8551161.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1661352 + ... + 1661448.

It is an arithmetic number, because the mean of its divisors is an integer number (2073435).

Almost surely, 2^161155800 is an apocalyptic number.

161155800 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 161155800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (298574640).

161155800 is an abundant number, since it is smaller than the sum of its proper divisors (435993480).

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

161155800 is a wasteful number, since it uses less digits than its factorization.

161155800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 27.

The square root of 161155800 is about 12694.7154359600. The cubic root of 161155800 is about 544.1876065019.

It can be divided in two parts, 161 and 155800, that added together give a triangular number (155961 = T₅₅₈).

The spelling of 161155800 in words is "one hundred sixty-one million, one hundred fifty-five thousand, eight hundred".