161217655 has 4 divisors (see below), whose sum is σ = 193461192. Its totient is φ = 128974120.

The previous prime is 161217643. The next prime is 161217659. The reversal of 161217655 is 556712161.

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

It is not a de Polignac number, because 161217655 - 2²¹ = 159120503 is a prime.

It is a super-2 number, since 2×161217655² = 51982264567398050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161217655.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161217659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16121761 + ... + 16121770.

It is an arithmetic number, because the mean of its divisors is an integer number (48365298).

Almost surely, 2^161217655 is an apocalyptic number.

161217655 is a deficient number, since it is larger than the sum of its proper divisors (32243537).

161217655 is an equidigital number, since it uses as much as digits as its factorization.

161217655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32243536.

The product of its digits is 12600, while the sum is 34.

The square root of 161217655 is about 12697.1514521959. The cubic root of 161217655 is about 544.2572211620.

The spelling of 161217655 in words is "one hundred sixty-one million, two hundred seventeen thousand, six hundred fifty-five".