166944521 has 2 divisors, whose sum is σ = 166944522. Its totient is φ = 166944520.

The previous prime is 166944487. The next prime is 166944523. The reversal of 166944521 is 125449661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 91948921 + 74995600 = 9589^2 + 8660^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166944521 is a prime.

It is a Sophie Germain prime.

Together with 166944523, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (166944523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83472260 + 83472261.

It is an arithmetic number, because the mean of its divisors is an integer number (83472261).

Almost surely, 2^166944521 is an apocalyptic number.

It is an amenable number.

166944521 is a deficient number, since it is larger than the sum of its proper divisors (1).

166944521 is an equidigital number, since it uses as much as digits as its factorization.

166944521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 38.

The square root of 166944521 is about 12920.7012580587. The cubic root of 166944521 is about 550.6268566253.

The spelling of 166944521 in words is "one hundred sixty-six million, nine hundred forty-four thousand, five hundred twenty-one".