165347521 has 4 divisors (see below), whose sum is σ = 170681344. Its totient is φ = 160013700.

The previous prime is 165347489. The next prime is 165347527. The reversal of 165347521 is 125743561.

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: 125743561 = 89 ⋅1412849.

It is a cyclic number.

It is not a de Polignac number, because 165347521 - 2⁵ = 165347489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165347527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2666865 + ... + 2666926.

It is an arithmetic number, because the mean of its divisors is an integer number (42670336).

Almost surely, 2^165347521 is an apocalyptic number.

It is an amenable number.

165347521 is a deficient number, since it is larger than the sum of its proper divisors (5333823).

165347521 is an equidigital number, since it uses as much as digits as its factorization.

165347521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5333822.

The product of its digits is 25200, while the sum is 34.

The square root of 165347521 is about 12858.7527000094. The cubic root of 165347521 is about 548.8654529867.

The spelling of 165347521 in words is "one hundred sixty-five million, three hundred forty-seven thousand, five hundred twenty-one".