9138809521 has 2 divisors, whose sum is σ = 9138809522. Its totient is φ = 9138809520.

The previous prime is 9138809497. The next prime is 9138809539. The reversal of 9138809521 is 1259088319.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5149497600 + 3989311921 = 71760^2 + 63161^2 .

It is an emirp because it is prime and its reverse (1259088319) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9138809521 - 2¹⁵ = 9138776753 is a prime.

It is a super-2 number, since 2×9138809521² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (9138809591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4569404760 + 4569404761.

It is an arithmetic number, because the mean of its divisors is an integer number (4569404761).

Almost surely, 2^9138809521 is an apocalyptic number.

It is an amenable number.

9138809521 is a deficient number, since it is larger than the sum of its proper divisors (1).

9138809521 is an equidigital number, since it uses as much as digits as its factorization.

9138809521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 155520, while the sum is 46.

The square root of 9138809521 is about 95597.1208823780. The cubic root of 9138809521 is about 2090.7232161314.

The spelling of 9138809521 in words is "nine billion, one hundred thirty-eight million, eight hundred nine thousand, five hundred twenty-one".