161825999 has 4 divisors (see below), whose sum is σ = 168861936. Its totient is φ = 154790064.

The previous prime is 161825987. The next prime is 161826001. The reversal of 161825999 is 999528161.

161825999 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: 999528161 = 7951 ⋅125711.

It is a cyclic number.

It is not a de Polignac number, because 161825999 - 2¹² = 161821903 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161825929) 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, 3517934 + ... + 3517979.

It is an arithmetic number, because the mean of its divisors is an integer number (42215484).

Almost surely, 2^161825999 is an apocalyptic number.

161825999 is a deficient number, since it is larger than the sum of its proper divisors (7035937).

161825999 is an equidigital number, since it uses as much as digits as its factorization.

161825999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7035936.

The product of its digits is 349920, while the sum is 50.

The square root of 161825999 is about 12721.0848200930. The cubic root of 161825999 is about 544.9409345971.

The spelling of 161825999 in words is "one hundred sixty-one million, eight hundred twenty-five thousand, nine hundred ninety-nine".