161901639843 has 16 divisors (see below), whose sum is σ = 225480702720. Its totient is φ = 103200771744.

The previous prime is 161901639829. The next prime is 161901639871. The reversal of 161901639843 is 348936109161.

161901639843 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 161901639843 - 2⁵ = 161901639811 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161901639883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9024721 + ... + 9042642.

It is an arithmetic number, because the mean of its divisors is an integer number (14092543920).

Almost surely, 2^161901639843 is an apocalyptic number.

161901639843 is a deficient number, since it is larger than the sum of its proper divisors (63579062877).

161901639843 is a wasteful number, since it uses less digits than its factorization.

161901639843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18067498.

The product of its (nonzero) digits is 839808, while the sum is 51.

The spelling of 161901639843 in words is "one hundred sixty-one billion, nine hundred one million, six hundred thirty-nine thousand, eight hundred forty-three".