72164381 has 2 divisors, whose sum is σ = 72164382. Its totient is φ = 72164380.

The previous prime is 72164359. The next prime is 72164401. The reversal of 72164381 is 18346127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69572281 + 2592100 = 8341^2 + 1610^2 .

It is an emirp because it is prime and its reverse (18346127) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72164381 is a prime.

It is a super-2 number, since 2×72164381² = 10415395770226322, which contains 22 as substring.

It is a Chen prime.

It is equal to p_4237808 and since 72164381 and 4237808 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72164681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36082190 + 36082191.

It is an arithmetic number, because the mean of its divisors is an integer number (36082191).

Almost surely, 2^72164381 is an apocalyptic number.

It is an amenable number.

72164381 is a deficient number, since it is larger than the sum of its proper divisors (1).

72164381 is an equidigital number, since it uses as much as digits as its factorization.

72164381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 32.

The square root of 72164381 is about 8494.9620952656. The cubic root of 72164381 is about 416.3331223647. Note that the first 3 decimals are identical.

The spelling of 72164381 in words is "seventy-two million, one hundred sixty-four thousand, three hundred eighty-one".