161291553 has 4 divisors (see below), whose sum is σ = 215055408. Its totient is φ = 107527700.

The previous prime is 161291549. The next prime is 161291573. The reversal of 161291553 is 355192161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 355192161 = 3 ⋅118397387.

It is a cyclic number.

It is not a de Polignac number, because 161291553 - 2² = 161291549 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161291573) 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 in 3 ways as a sum of consecutive naturals, for example, 26881923 + ... + 26881928.

It is an arithmetic number, because the mean of its divisors is an integer number (53763852).

Almost surely, 2^161291553 is an apocalyptic number.

It is an amenable number.

161291553 is a deficient number, since it is larger than the sum of its proper divisors (53763855).

161291553 is an equidigital number, since it uses as much as digits as its factorization.

161291553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53763854.

The product of its digits is 8100, while the sum is 33.

The square root of 161291553 is about 12700.0611415851. The cubic root of 161291553 is about 544.3403662669.

The spelling of 161291553 in words is "one hundred sixty-one million, two hundred ninety-one thousand, five hundred fifty-three".