164194381 has 16 divisors (see below), whose sum is σ = 191803248. Its totient is φ = 139161600.

The previous prime is 164194367. The next prime is 164194391. The reversal of 164194381 is 183491461.

164194381 is a nontrivial binomial coefficient, being equal to C(18122, 2).

It can be written as a sum of positive squares in 8 ways, for example, as 25755625 + 138438756 = 5075^2 + 11766^2 .

It is a 6-Lehmer number, since φ(164194381) divides (164194381-1)⁶.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-164194381 is a prime.

It is a super-2 number, since 2×164194381² = 53919589503946322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 164194381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164194391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1 + ... + 18121.

It is an arithmetic number, because the mean of its divisors is an integer number (11987703).

Almost surely, 2^164194381 is an apocalyptic number.

164194381 is the 18121-st triangular number and also the 9061-st hexagonal number.

164194381 is the 6041-st centered nonagonal number.

It is an amenable number.

164194381 is a deficient number, since it is larger than the sum of its proper divisors (27608867).

164194381 is a wasteful number, since it uses less digits than its factorization.

164194381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18192.

The product of its digits is 20736, while the sum is 37.

The square root of 164194381 is about 12813.8355303945. The cubic root of 164194381 is about 547.5865390059.

The spelling of 164194381 in words is "one hundred sixty-four million, one hundred ninety-four thousand, three hundred eighty-one".