138081357649 has 9 divisors (see below), whose sum is σ = 138916117809. Its totient is φ = 137251590480.

The previous prime is 138081357641. The next prime is 138081357679. The reversal of 138081357649 is 946753180831.

The square root of 138081357649 is 371593.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 52447870225 + 85633487424 = 229015^2 + 292632^2 .

It is not a de Polignac number, because 138081357649 - 2³ = 138081357641 is a prime.

It is a super-2 number, since 2×138081357649² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 138081357649.

It is not an unprimeable number, because it can be changed into a prime (138081357641) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 67257307 + ... + 67259359.

It is an arithmetic number, because the mean of its divisors is an integer number (15435124201).

Almost surely, 2^138081357649 is an apocalyptic number.

138081357649 is the 371593-rd square number.

138081357649 is the 185797-th centered octagonal number.

It is an amenable number.

138081357649 is a deficient number, since it is larger than the sum of its proper divisors (834760160).

138081357649 is an frugal number, since it uses more digits than its factorization.

138081357649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4468 (or 2234 counting only the distinct ones).

The product of its (nonzero) digits is 4354560, while the sum is 55.

The spelling of 138081357649 in words is "one hundred thirty-eight billion, eighty-one million, three hundred fifty-seven thousand, six hundred forty-nine".