166564159901 has 4 divisors (see below), whose sum is σ = 166811655612. Its totient is φ = 166316664192.

The previous prime is 166564159897. The next prime is 166564159921. The reversal of 166564159901 is 109951465661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 109951465661 = 23 ⋅4780498507.

It can be written as a sum of positive squares in 2 ways, for example, as 51134776900 + 115429383001 = 226130^2 + 339749^2 .

It is a cyclic number.

It is not a de Polignac number, because 166564159901 - 2² = 166564159897 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166564159921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 123746846 + ... + 123748191.

It is an arithmetic number, because the mean of its divisors is an integer number (41702913903).

Almost surely, 2^166564159901 is an apocalyptic number.

It is an amenable number.

166564159901 is a deficient number, since it is larger than the sum of its proper divisors (247495711).

166564159901 is an equidigital number, since it uses as much as digits as its factorization.

166564159901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247495710.

The product of its (nonzero) digits is 1749600, while the sum is 53.

The spelling of 166564159901 in words is "one hundred sixty-six billion, five hundred sixty-four million, one hundred fifty-nine thousand, nine hundred one".