161551066 has 4 divisors (see below), whose sum is σ = 242326602. Its totient is φ = 80775532.

The previous prime is 161551063. The next prime is 161551067. The reversal of 161551066 is 660155161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 660155161 = 4409 ⋅149729.

It can be written as a sum of positive squares in only one way, i.e., 127035441 + 34515625 = 11271^2 + 5875^2 .

It is not an unprimeable number, because it can be changed into a prime (161551063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40387765 + ... + 40387768.

Almost surely, 2^161551066 is an apocalyptic number.

161551066 is a deficient number, since it is larger than the sum of its proper divisors (80775536).

161551066 is an equidigital number, since it uses as much as digits as its factorization.

161551066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80775535.

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 161551066 is about 12710.2740332378. The cubic root of 161551066 is about 544.6321519674.

The spelling of 161551066 in words is "one hundred sixty-one million, five hundred fifty-one thousand, sixty-six".