165523661 has 2 divisors, whose sum is σ = 165523662. Its totient is φ = 165523660.

The previous prime is 165523639. The next prime is 165523667. The reversal of 165523661 is 166325561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 113827561 + 51696100 = 10669^2 + 7190^2 .

It is a cyclic number.

It is not a de Polignac number, because 165523661 - 2⁶ = 165523597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165523667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82761830 + 82761831.

It is an arithmetic number, because the mean of its divisors is an integer number (82761831).

Almost surely, 2^165523661 is an apocalyptic number.

It is an amenable number.

165523661 is a deficient number, since it is larger than the sum of its proper divisors (1).

165523661 is an equidigital number, since it uses as much as digits as its factorization.

165523661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32400, while the sum is 35.

The square root of 165523661 is about 12865.5999082826. The cubic root of 165523661 is about 549.0602807279.

The spelling of 165523661 in words is "one hundred sixty-five million, five hundred twenty-three thousand, six hundred sixty-one".