161504551 has 8 divisors (see below), whose sum is σ = 181490400. Its totient is φ = 142599072.

The previous prime is 161504533. The next prime is 161504561. The reversal of 161504551 is 155405161.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161504551 - 2⁷ = 161504423 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161504561) 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 7 ways as a sum of consecutive naturals, for example, 269776 + ... + 270373.

It is an arithmetic number, because the mean of its divisors is an integer number (22686300).

Almost surely, 2^161504551 is an apocalyptic number.

161504551 is a deficient number, since it is larger than the sum of its proper divisors (19985849).

161504551 is a wasteful number, since it uses less digits than its factorization.

161504551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540185.

The product of its (nonzero) digits is 3000, while the sum is 28.

The square root of 161504551 is about 12708.4440825775. Note that the first 3 decimals coincide. The cubic root of 161504551 is about 544.5798754190.

The spelling of 161504551 in words is "one hundred sixty-one million, five hundred four thousand, five hundred fifty-one".