72389813 has 2 divisors, whose sum is σ = 72389814. Its totient is φ = 72389812.

The previous prime is 72389789. The next prime is 72389819. The reversal of 72389813 is 31898327.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72301009 + 88804 = 8503^2 + 298^2 .

It is an emirp because it is prime and its reverse (31898327) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72389813 - 2²⁶ = 5280949 is a prime.

It is a super-3 number, since 3×72389813³ (a number of 25 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72389819) 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, 36194906 + 36194907.

It is an arithmetic number, because the mean of its divisors is an integer number (36194907).

Almost surely, 2^72389813 is an apocalyptic number.

It is an amenable number.

72389813 is a deficient number, since it is larger than the sum of its proper divisors (1).

72389813 is an equidigital number, since it uses as much as digits as its factorization.

72389813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 41.

The square root of 72389813 is about 8508.2203191972. The cubic root of 72389813 is about 416.7661949618.

The spelling of 72389813 in words is "seventy-two million, three hundred eighty-nine thousand, eight hundred thirteen".