161901857159 has 4 divisors (see below), whose sum is σ = 185030693904. Its totient is φ = 138773020416.

The previous prime is 161901857149. The next prime is 161901857177. The reversal of 161901857159 is 951758109161.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161901857159 - 2¹² = 161901853063 is a prime.

It is a super-2 number, since 2×161901857159² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 161901857159.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161901857119) 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 3 ways as a sum of consecutive naturals, for example, 11564418362 + ... + 11564418375.

It is an arithmetic number, because the mean of its divisors is an integer number (46257673476).

Almost surely, 2^161901857159 is an apocalyptic number.

161901857159 is a deficient number, since it is larger than the sum of its proper divisors (23128836745).

161901857159 is an equidigital number, since it uses as much as digits as its factorization.

161901857159 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23128836744.

The product of its (nonzero) digits is 680400, while the sum is 53.

The spelling of 161901857159 in words is "one hundred sixty-one billion, nine hundred one million, eight hundred fifty-seven thousand, one hundred fifty-nine".