165531541 has 4 divisors (see below), whose sum is σ = 189178912. Its totient is φ = 141884172.

The previous prime is 165531539. The next prime is 165531547. The reversal of 165531541 is 145135561.

It is a happy number.

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: 145135561 = 79 ⋅1837159.

It is a cyclic number.

It is not a de Polignac number, because 165531541 - 2¹ = 165531539 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 (165531547) 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, 11823675 + ... + 11823688.

It is an arithmetic number, because the mean of its divisors is an integer number (47294728).

Almost surely, 2^165531541 is an apocalyptic number.

It is an amenable number.

165531541 is a deficient number, since it is larger than the sum of its proper divisors (23647371).

165531541 is an equidigital number, since it uses as much as digits as its factorization.

165531541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23647370.

The product of its digits is 9000, while the sum is 31.

The square root of 165531541 is about 12865.9061476446. The cubic root of 165531541 is about 549.0689935333.

The spelling of 165531541 in words is "one hundred sixty-five million, five hundred thirty-one thousand, five hundred forty-one".