166124421661 has 16 divisors (see below), whose sum is σ = 185356304640. Its totient is φ = 147590322880.

The previous prime is 166124421613. The next prime is 166124421691.

It is a happy number.

166124421661 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 166124421661 - 2²³ = 166116033053 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 (166124421691) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 112695 + ... + 587323.

It is an arithmetic number, because the mean of its divisors is an integer number (11584769040).

Almost surely, 2^166124421661 is an apocalyptic number.

166124421661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

166124421661 is a deficient number, since it is larger than the sum of its proper divisors (19231882979).

166124421661 is a wasteful number, since it uses less digits than its factorization.

166124421661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475364.

The product of its digits is 82944, while the sum is 40.

It can be divided in two parts, 166124 and 421661, that added together give a palindrome (587785).

The spelling of 166124421661 in words is "one hundred sixty-six billion, one hundred twenty-four million, four hundred twenty-one thousand, six hundred sixty-one".