166216015501 has 2 divisors, whose sum is σ = 166216015502. Its totient is φ = 166216015500.

The previous prime is 166216015499. The next prime is 166216015571. The reversal of 166216015501 is 105510612661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 158743277476 + 7472738025 = 398426^2 + 86445^2 .

It is a cyclic number.

It is not a de Polignac number, because 166216015501 - 2¹ = 166216015499 is a prime.

Together with 166216015499, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166216015571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83108007750 + 83108007751.

It is an arithmetic number, because the mean of its divisors is an integer number (83108007751).

Almost surely, 2^166216015501 is an apocalyptic number.

It is an amenable number.

166216015501 is a deficient number, since it is larger than the sum of its proper divisors (1).

166216015501 is an equidigital number, since it uses as much as digits as its factorization.

166216015501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10800, while the sum is 34.

The spelling of 166216015501 in words is "one hundred sixty-six billion, two hundred sixteen million, fifteen thousand, five hundred one".