139081581 has 6 divisors (see below), whose sum is σ = 200895630. Its totient is φ = 92721048.

The previous prime is 139081567. The next prime is 139081583. The reversal of 139081581 is 185180931.

139081581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 124679556 + 14402025 = 11166^2 + 3795^2 .

It is not a de Polignac number, because 139081581 - 2¹⁴ = 139065197 is a prime.

It is a super-2 number, since 2×139081581² = 38687372346919122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139081583) 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, 7726746 + ... + 7726763.

It is an arithmetic number, because the mean of its divisors is an integer number (33482605).

Almost surely, 2^139081581 is an apocalyptic number.

It is an amenable number.

139081581 is a deficient number, since it is larger than the sum of its proper divisors (61814049).

139081581 is a wasteful number, since it uses less digits than its factorization.

139081581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15453515 (or 15453512 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 36.

The square root of 139081581 is about 11793.2854201024. The cubic root of 139081581 is about 518.1114693300. Note that the first 3 decimals are identical.

The spelling of 139081581 in words is "one hundred thirty-nine million, eighty-one thousand, five hundred eighty-one".