166238667401 has 4 divisors (see below), whose sum is σ = 167763792900. Its totient is φ = 164713541904.

The previous prime is 166238667323. The next prime is 166238667421. The reversal of 166238667401 is 104766832661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 104766832661 = 154571 ⋅677791.

It can be written as a sum of positive squares in 2 ways, for example, as 125157458176 + 41081209225 = 353776^2 + 202685^2 .

It is a cyclic number.

It is not a de Polignac number, because 166238667401 - 2¹⁴ = 166238651017 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 166238667401.

It is not an unprimeable number, because it can be changed into a prime (166238667421) 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, 762562586 + ... + 762562803.

It is an arithmetic number, because the mean of its divisors is an integer number (41940948225).

Almost surely, 2^166238667401 is an apocalyptic number.

It is an amenable number.

166238667401 is a deficient number, since it is larger than the sum of its proper divisors (1525125499).

166238667401 is a wasteful number, since it uses less digits than its factorization.

166238667401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1525125498.

The product of its (nonzero) digits is 1741824, while the sum is 50.

The spelling of 166238667401 in words is "one hundred sixty-six billion, two hundred thirty-eight million, six hundred sixty-seven thousand, four hundred one".