166242139523 has 4 divisors (see below), whose sum is σ = 166242955800. Its totient is φ = 166241323248.

The previous prime is 166242139447. The next prime is 166242139561. The reversal of 166242139523 is 325931242661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 325931242661 = 197 ⋅1654473313.

It is a cyclic number.

It is not a de Polignac number, because 166242139523 - 2¹⁴ = 166242123139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166242139823) 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, 176636 + ... + 603062.

It is an arithmetic number, because the mean of its divisors is an integer number (41560738950).

Almost surely, 2^166242139523 is an apocalyptic number.

166242139523 is a deficient number, since it is larger than the sum of its proper divisors (816277).

166242139523 is an equidigital number, since it uses as much as digits as its factorization.

166242139523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 816276.

The product of its digits is 466560, while the sum is 44.

The spelling of 166242139523 in words is "one hundred sixty-six billion, two hundred forty-two million, one hundred thirty-nine thousand, five hundred twenty-three".