161861544 has 128 divisors (see below), whose sum is σ = 492912000. Its totient is φ = 48909312.

The previous prime is 161861543. The next prime is 161861549. The reversal of 161861544 is 445168161.

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

It is a junction number, because it is equal to n+sod(n) for n = 161861499 and 161861508.

It is not an unprimeable number, because it can be changed into a prime (161861543) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 165184 + ... + 166160.

It is an arithmetic number, because the mean of its divisors is an integer number (3850875).

Almost surely, 2^161861544 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161861544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (246456000).

161861544 is an abundant number, since it is smaller than the sum of its proper divisors (331050456).

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

161861544 is a wasteful number, since it uses less digits than its factorization.

161861544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1064 (or 1054 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 161861544 is about 12722.4818333531. The cubic root of 161861544 is about 544.9808303445.

The spelling of 161861544 in words is "one hundred sixty-one million, eight hundred sixty-one thousand, five hundred forty-four".