165585421 has 2 divisors, whose sum is σ = 165585422. Its totient is φ = 165585420.

The previous prime is 165585401. The next prime is 165585439. The reversal of 165585421 is 124585561.

165585421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 145684900 + 19900521 = 12070^2 + 4461^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165585421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165585401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82792710 + 82792711.

It is an arithmetic number, because the mean of its divisors is an integer number (82792711).

Almost surely, 2^165585421 is an apocalyptic number.

It is an amenable number.

165585421 is a deficient number, since it is larger than the sum of its proper divisors (1).

165585421 is an equidigital number, since it uses as much as digits as its factorization.

165585421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48000, while the sum is 37.

The square root of 165585421 is about 12867.9998834318. Note that the first 3 decimals coincide. The cubic root of 165585421 is about 549.1285604854.

The spelling of 165585421 in words is "one hundred sixty-five million, five hundred eighty-five thousand, four hundred twenty-one".