161881560 has 48 divisors (see below), whose sum is σ = 526116240. Its totient is φ = 43168320.

The previous prime is 161881543. The next prime is 161881561. The reversal of 161881560 is 65188161.

161881560 is a `hidden beast` number, since 1 + 6 + 18 + 81 + 560 = 666.

161881560 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161881561) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 224476 + ... + 225195.

It is an arithmetic number, because the mean of its divisors is an integer number (10960755).

Almost surely, 2^161881560 is an apocalyptic number.

161881560 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161881560 is an abundant number, since it is smaller than the sum of its proper divisors (364234680).

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

161881560 is a wasteful number, since it uses less digits than its factorization.

161881560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449688 (or 449681 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 161881560 is about 12723.2684480050. The cubic root of 161881560 is about 545.0032937545.

It can be divided in two parts, 161 and 881560, that added together give a square (881721 = 939²).

The spelling of 161881560 in words is "one hundred sixty-one million, eight hundred eighty-one thousand, five hundred sixty".