161642999 has 4 divisors (see below), whose sum is σ = 184734864. Its totient is φ = 138551136.

The previous prime is 161642983. The next prime is 161643017. The reversal of 161642999 is 999246161.

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 161642999 - 2⁴ = 161642983 is a prime.

It is a super-2 number, since 2×161642999² = 52256918251428002, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161642399) 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, 11545922 + ... + 11545935.

It is an arithmetic number, because the mean of its divisors is an integer number (46183716).

Almost surely, 2^161642999 is an apocalyptic number.

161642999 is a deficient number, since it is larger than the sum of its proper divisors (23091865).

161642999 is an equidigital number, since it uses as much as digits as its factorization.

161642999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23091864.

The product of its digits is 209952, while the sum is 47.

The square root of 161642999 is about 12713.8900026703. The cubic root of 161642999 is about 544.7354426776.

The spelling of 161642999 in words is "one hundred sixty-one million, six hundred forty-two thousand, nine hundred ninety-nine".