163666501 has 2 divisors, whose sum is σ = 163666502. Its totient is φ = 163666500.

The previous prime is 163666499. The next prime is 163666543. The reversal of 163666501 is 105666361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 119377476 + 44289025 = 10926^2 + 6655^2 .

It is a cyclic number.

It is not a de Polignac number, because 163666501 - 2¹ = 163666499 is a prime.

Together with 163666499, 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 (163666201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81833250 + 81833251.

It is an arithmetic number, because the mean of its divisors is an integer number (81833251).

Almost surely, 2^163666501 is an apocalyptic number.

It is an amenable number.

163666501 is a deficient number, since it is larger than the sum of its proper divisors (1).

163666501 is an equidigital number, since it uses as much as digits as its factorization.

163666501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 34.

The square root of 163666501 is about 12793.2209001486. The cubic root of 163666501 is about 546.9990842506. Note that the first 3 decimals are identical.

The spelling of 163666501 in words is "one hundred sixty-three million, six hundred sixty-six thousand, five hundred one".