169920561 has 4 divisors (see below), whose sum is σ = 226560752. Its totient is φ = 113280372.

The previous prime is 169920533. The next prime is 169920571. The reversal of 169920561 is 165029961.

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.

It is not a de Polignac number, because 169920561 - 2⁵ = 169920529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (169920511) 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, 28320091 + ... + 28320096.

It is an arithmetic number, because the mean of its divisors is an integer number (56640188).

Almost surely, 2^169920561 is an apocalyptic number.

It is an amenable number.

169920561 is a deficient number, since it is larger than the sum of its proper divisors (56640191).

169920561 is an equidigital number, since it uses as much as digits as its factorization.

169920561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56640190.

The product of its (nonzero) digits is 29160, while the sum is 39.

The square root of 169920561 is about 13035.3581078542. The cubic root of 169920561 is about 553.8795249939.

The spelling of 169920561 in words is "one hundred sixty-nine million, nine hundred twenty thousand, five hundred sixty-one".