165861001 has 2 divisors, whose sum is σ = 165861002. Its totient is φ = 165861000.

The previous prime is 165860969. The next prime is 165861011. The reversal of 165861001 is 100168561.

165861001 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., 147379600 + 18481401 = 12140^2 + 4299^2 .

It is a cyclic number.

It is not a de Polignac number, because 165861001 - 2⁵ = 165860969 is a prime.

It is not a weakly prime, because it can be changed into another prime (165861011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82930500 + 82930501.

It is an arithmetic number, because the mean of its divisors is an integer number (82930501).

Almost surely, 2^165861001 is an apocalyptic number.

It is an amenable number.

165861001 is a deficient number, since it is larger than the sum of its proper divisors (1).

165861001 is an equidigital number, since it uses as much as digits as its factorization.

165861001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 165861001 is about 12878.7033897050. The cubic root of 165861001 is about 549.4330256456.

The spelling of 165861001 in words is "one hundred sixty-five million, eight hundred sixty-one thousand, one".