161978280 has 64 divisors (see below), whose sum is σ = 488194560. Its totient is φ = 42993408.

The previous prime is 161978273. The next prime is 161978293. The reversal of 161978280 is 82879161.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23734 + ... + 29786.

It is an arithmetic number, because the mean of its divisors is an integer number (7628040).

Almost surely, 2^161978280 is an apocalyptic number.

161978280 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 161978280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (244097280).

161978280 is an abundant number, since it is smaller than the sum of its proper divisors (326216280).

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

161978280 is a wasteful number, since it uses less digits than its factorization.

161978280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6290 (or 6286 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 42.

The square root of 161978280 is about 12727.0687905739. The cubic root of 161978280 is about 545.1118138847. Note that the first 3 decimals are identical.

The spelling of 161978280 in words is "one hundred sixty-one million, nine hundred seventy-eight thousand, two hundred eighty".