161640238 has 16 divisors (see below), whose sum is σ = 248002560. Its totient is φ = 78978136.

The previous prime is 161640221. The next prime is 161640253. The reversal of 161640238 is 832046161.

It is a happy number.

It is a super-2 number, since 2×161640238² = 52255133081393288, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102903 + ... + 104461.

It is an arithmetic number, because the mean of its divisors is an integer number (15500160).

Almost surely, 2^161640238 is an apocalyptic number.

161640238 is a deficient number, since it is larger than the sum of its proper divisors (86362322).

161640238 is a wasteful number, since it uses less digits than its factorization.

161640238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2711.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 161640238 is about 12713.7814201755. The cubic root of 161640238 is about 544.7323411449.

Adding to 161640238 its reverse (832046161), we get a palindrome (993686399).

The spelling of 161640238 in words is "one hundred sixty-one million, six hundred forty thousand, two hundred thirty-eight".