161581139099 has 8 divisors (see below), whose sum is σ = 161979809712. Its totient is φ = 161182586880.

The previous prime is 161581139059. The next prime is 161581139149. The reversal of 161581139099 is 990931185161.

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 161581139099 - 2⁸ = 161581138843 is a prime.

It is a super-2 number, since 2×161581139099² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161581139099.

It is not an unprimeable number, because it can be changed into a prime (161581139009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3110459 + ... + 3161979.

It is an arithmetic number, because the mean of its divisors is an integer number (20247476214).

Almost surely, 2^161581139099 is an apocalyptic number.

161581139099 is a deficient number, since it is larger than the sum of its proper divisors (398670613).

161581139099 is an equidigital number, since it uses as much as digits as its factorization.

161581139099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59197.

The product of its (nonzero) digits is 524880, while the sum is 53.

The spelling of 161581139099 in words is "one hundred sixty-one billion, five hundred eighty-one million, one hundred thirty-nine thousand, ninety-nine".