161773920 has 288 divisors, whose sum is σ = 688746240. Its totient is φ = 33592320.

The previous prime is 161773907. The next prime is 161773991. The reversal of 161773920 is 29377161.

It is a happy number.

161773920 is a `hidden beast` number, since 1 + 617 + 7 + 39 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

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, 110151 + ... + 111609.

It is an arithmetic number, because the mean of its divisors is an integer number (2391480).

Almost surely, 2^161773920 is an apocalyptic number.

161773920 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 161773920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (344373120).

161773920 is an abundant number, since it is smaller than the sum of its proper divisors (526972320).

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

161773920 is a wasteful number, since it uses less digits than its factorization.

With its predecessor (161773919) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (1498).

161773920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1498 (or 1487 counting only the distinct ones).

The product of its (nonzero) digits is 15876, while the sum is 36.

The square root of 161773920 is about 12719.0376994488. The cubic root of 161773920 is about 544.8824705183.

The spelling of 161773920 in words is "one hundred sixty-one million, seven hundred seventy-three thousand, nine hundred twenty".