161440381 has 8 divisors (see below), whose sum is σ = 178369344. Its totient is φ = 145337280.

The previous prime is 161440379. The next prime is 161440399. The reversal of 161440381 is 183044161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161440381 - 2¹ = 161440379 is a prime.

It is a super-2 number, since 2×161440381² = 52125993234850322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161440481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 206055 + ... + 206836.

It is an arithmetic number, because the mean of its divisors is an integer number (22296168).

Almost surely, 2^161440381 is an apocalyptic number.

It is an amenable number.

161440381 is a deficient number, since it is larger than the sum of its proper divisors (16928963).

161440381 is a wasteful number, since it uses less digits than its factorization.

161440381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412931.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 161440381 is about 12705.9191324359. The cubic root of 161440381 is about 544.5077405686.

The spelling of 161440381 in words is "one hundred sixty-one million, four hundred forty thousand, three hundred eighty-one".