161671553 has 4 divisors (see below), whose sum is σ = 162564948. Its totient is φ = 160778160.

The previous prime is 161671511. The next prime is 161671579. The reversal of 161671553 is 355176161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 355176161 = 53 ⋅6701437.

It can be written as a sum of positive squares in 2 ways, for example, as 19775809 + 141895744 = 4447^2 + 11912^2 .

It is a cyclic number.

It is not a de Polignac number, because 161671553 - 2⁸ = 161671297 is a prime.

It is a super-2 number, since 2×161671553² = 52275382098863618, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (161671583) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 446426 + ... + 446787.

It is an arithmetic number, because the mean of its divisors is an integer number (40641237).

Almost surely, 2^161671553 is an apocalyptic number.

It is an amenable number.

161671553 is a deficient number, since it is larger than the sum of its proper divisors (893395).

161671553 is an equidigital number, since it uses as much as digits as its factorization.

161671553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 893394.

The product of its digits is 18900, while the sum is 35.

The square root of 161671553 is about 12715.0128981452. The cubic root of 161671553 is about 544.7675163629.

The spelling of 161671553 in words is "one hundred sixty-one million, six hundred seventy-one thousand, five hundred fifty-three".