161815859 has 4 divisors (see below), whose sum is σ = 164468640. Its totient is φ = 159163080.

The previous prime is 161815789. The next prime is 161815861. The reversal of 161815859 is 958518161.

161815859 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 958518161 = 9623 ⋅99607.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161815859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161814859) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1326299 + ... + 1326420.

It is an arithmetic number, because the mean of its divisors is an integer number (41117160).

Almost surely, 2^161815859 is an apocalyptic number.

161815859 is a deficient number, since it is larger than the sum of its proper divisors (2652781).

161815859 is an equidigital number, since it uses as much as digits as its factorization.

161815859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2652780.

The product of its digits is 86400, while the sum is 44.

The square root of 161815859 is about 12720.6862629341. The cubic root of 161815859 is about 544.9295523789.

The spelling of 161815859 in words is "one hundred sixty-one million, eight hundred fifteen thousand, eight hundred fifty-nine".