161639266 has 4 divisors (see below), whose sum is σ = 242458902. Its totient is φ = 80819632.

The previous prime is 161639221. The next prime is 161639267. The reversal of 161639266 is 662936161.

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

It can be written as a sum of positive squares in only one way, i.e., 153636025 + 8003241 = 12395^2 + 2829^2 .

It is a super-2 number, since 2×161639266² = 52254504626037512, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (161639267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40409815 + ... + 40409818.

Almost surely, 2^161639266 is an apocalyptic number.

161639266 is a deficient number, since it is larger than the sum of its proper divisors (80819636).

161639266 is an equidigital number, since it uses as much as digits as its factorization.

161639266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80819635.

The product of its digits is 69984, while the sum is 40.

The square root of 161639266 is about 12713.7431938828. The cubic root of 161639266 is about 544.7312492532.

The spelling of 161639266 in words is "one hundred sixty-one million, six hundred thirty-nine thousand, two hundred sixty-six".