166142521 has 2 divisors, whose sum is σ = 166142522. Its totient is φ = 166142520.

The previous prime is 166142519. The next prime is 166142527. The reversal of 166142521 is 125241661.

166142521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 155351296 + 10791225 = 12464^2 + 3285^2 .

It is an emirp because it is prime and its reverse (125241661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 166142521 - 2¹ = 166142519 is a prime.

Together with 166142519, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 166142521.

It is not a weakly prime, because it can be changed into another prime (166142527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83071260 + 83071261.

It is an arithmetic number, because the mean of its divisors is an integer number (83071261).

Almost surely, 2^166142521 is an apocalyptic number.

It is an amenable number.

166142521 is a deficient number, since it is larger than the sum of its proper divisors (1).

166142521 is an equidigital number, since it uses as much as digits as its factorization.

166142521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 28.

The square root of 166142521 is about 12889.6284275382. The cubic root of 166142521 is about 549.7437053812.

The spelling of 166142521 in words is "one hundred sixty-six million, one hundred forty-two thousand, five hundred twenty-one".