166115505116501 has 2 divisors, whose sum is σ = 166115505116502. Its totient is φ = 166115505116500.

The previous prime is 166115505116383. The next prime is 166115505116531. The reversal of 166115505116501 is 105611505511661.

166115505116501 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., 152916125837476 + 13199379279025 = 12365926^2 + 3633095^2 .

It is a cyclic number.

It is not a de Polignac number, because 166115505116501 - 2¹⁰ = 166115505115477 is a prime.

It is a super-2 number, since 2×166115505116501² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166115505116531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83057752558250 + 83057752558251.

It is an arithmetic number, because the mean of its divisors is an integer number (83057752558251).

Almost surely, 2^{166115505116501} is an apocalyptic number.

It is an amenable number.

166115505116501 is a deficient number, since it is larger than the sum of its proper divisors (1).

166115505116501 is an equidigital number, since it uses as much as digits as its factorization.

166115505116501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 135000, while the sum is 44.

The spelling of 166115505116501 in words is "one hundred sixty-six trillion, one hundred fifteen billion, five hundred five million, one hundred sixteen thousand, five hundred one".