138451712281 has 9 divisors (see below), whose sum is σ = 138906780831. Its totient is φ = 137998133352.

The previous prime is 138451712279. The next prime is 138451712293. The reversal of 138451712281 is 182217154831.

It is a happy number.

The square root of 138451712281 is 372091.

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

It can be written as a sum of positive squares in only one way, i.e., 451350025 + 138000362256 = 21245^2 + 371484^2 .

It is not a de Polignac number, because 138451712281 - 2¹ = 138451712279 is a prime.

It is a super-2 number, since 2×138451712281² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138451712251) 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, 225858931 + ... + 225859543.

It is an arithmetic number, because the mean of its divisors is an integer number (15434086759).

Almost surely, 2^138451712281 is an apocalyptic number.

138451712281 is the 372091-st square number.

138451712281 is the 186046-th centered octagonal number.

It is an amenable number.

138451712281 is a deficient number, since it is larger than the sum of its proper divisors (455068550).

138451712281 is an frugal number, since it uses more digits than its factorization.

138451712281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2440 (or 1220 counting only the distinct ones).

The product of its digits is 107520, while the sum is 43.

The spelling of 138451712281 in words is "one hundred thirty-eight billion, four hundred fifty-one million, seven hundred twelve thousand, two hundred eighty-one".