138455581 has 6 divisors (see below), whose sum is σ = 152186846. Its totient is φ = 125868600.

The previous prime is 138455573. The next prime is 138455593. The reversal of 138455581 is 185554831.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 127125625 + 11329956 = 11275^2 + 3366^2 .

It is not a de Polignac number, because 138455581 - 2³ = 138455573 is a prime.

It is a super-2 number, since 2×138455581² = 38339895820095122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138455281) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 572010 + ... + 572251.

Almost surely, 2^138455581 is an apocalyptic number.

138455581 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

138455581 is a deficient number, since it is larger than the sum of its proper divisors (13731265).

138455581 is a wasteful number, since it uses less digits than its factorization.

138455581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1144283 (or 1144272 counting only the distinct ones).

The product of its digits is 96000, while the sum is 40.

The square root of 138455581 is about 11766.7149621294. The cubic root of 138455581 is about 517.3329679453.

It can be divided in two parts, 1384 and 55581, that added together give a palindrome (56965).

The spelling of 138455581 in words is "one hundred thirty-eight million, four hundred fifty-five thousand, five hundred eighty-one".