72891081869 has 2 divisors, whose sum is σ = 72891081870. Its totient is φ = 72891081868.

The previous prime is 72891081821. The next prime is 72891081881. The reversal of 72891081869 is 96818019827.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71933922025 + 957159844 = 268205^2 + 30938^2 .

It is an emirp because it is prime and its reverse (96818019827) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72891081869 - 2¹⁶ = 72891016333 is a prime.

It is a super-2 number, since 2×72891081869² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72891081569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36445540934 + 36445540935.

It is an arithmetic number, because the mean of its divisors is an integer number (36445540935).

Almost surely, 2^72891081869 is an apocalyptic number.

It is an amenable number.

72891081869 is a deficient number, since it is larger than the sum of its proper divisors (1).

72891081869 is an equidigital number, since it uses as much as digits as its factorization.

72891081869 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3483648, while the sum is 59.

The spelling of 72891081869 in words is "seventy-two billion, eight hundred ninety-one million, eighty-one thousand, eight hundred sixty-nine".