166725661 has 2 divisors, whose sum is σ = 166725662. Its totient is φ = 166725660.

The previous prime is 166725653. The next prime is 166725677. The reversal of 166725661 is 166527661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 155875225 + 10850436 = 12485^2 + 3294^2 .

It is an emirp because it is prime and its reverse (166527661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 166725661 - 2³ = 166725653 is a prime.

It is a super-3 number, since 3×166725661³ (a number of 26 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166725641) 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 as a sum of consecutive naturals, namely, 83362830 + 83362831.

It is an arithmetic number, because the mean of its divisors is an integer number (83362831).

Almost surely, 2^166725661 is an apocalyptic number.

It is an amenable number.

166725661 is a deficient number, since it is larger than the sum of its proper divisors (1).

166725661 is an equidigital number, since it uses as much as digits as its factorization.

166725661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 40.

The square root of 166725661 is about 12912.2291259101. The cubic root of 166725661 is about 550.3861321550.

The spelling of 166725661 in words is "one hundred sixty-six million, seven hundred twenty-five thousand, six hundred sixty-one".