161541640 has 64 divisors (see below), whose sum is σ = 401027760. Its totient is φ = 58183680.

The previous prime is 161541637. The next prime is 161541643. The reversal of 161541640 is 46145161.

161541640 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (161541637) and next prime (161541643).

It can be written as a sum of positive squares in 8 ways, for example, as 2125764 + 159415876 = 1458^2 + 12626^2 .

It is a junction number, because it is equal to n+sod(n) for n = 161541599 and 161541608.

It is not an unprimeable number, because it can be changed into a prime (161541643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17532 + ... + 25108.

Almost surely, 2^161541640 is an apocalyptic number.

161541640 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 161541640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (200513880).

161541640 is an abundant number, since it is smaller than the sum of its proper divisors (239486120).

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

161541640 is a wasteful number, since it uses less digits than its factorization.

161541640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7642 (or 7638 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 161541640 is about 12709.9032254380. The cubic root of 161541640 is about 544.6215592332.

The spelling of 161541640 in words is "one hundred sixty-one million, five hundred forty-one thousand, six hundred forty".