161757551 has 4 divisors (see below), whose sum is σ = 168790512. Its totient is φ = 154724592.

The previous prime is 161757539. The next prime is 161757553. The reversal of 161757551 is 155757161.

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

It is a cyclic number.

It is not a de Polignac number, because 161757551 - 2¹⁰ = 161756527 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161757553) 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, 3516446 + ... + 3516491.

It is an arithmetic number, because the mean of its divisors is an integer number (42197628).

Almost surely, 2^161757551 is an apocalyptic number.

161757551 is a deficient number, since it is larger than the sum of its proper divisors (7032961).

161757551 is an equidigital number, since it uses as much as digits as its factorization.

161757551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7032960.

The product of its digits is 36750, while the sum is 38.

The square root of 161757551 is about 12718.3941989545. The cubic root of 161757551 is about 544.8640920264.

The spelling of 161757551 in words is "one hundred sixty-one million, seven hundred fifty-seven thousand, five hundred fifty-one".