185139481 has 4 divisors (see below), whose sum is σ = 185339700. Its totient is φ = 184939264.

The previous prime is 185139473. The next prime is 185139499. The reversal of 185139481 is 184931581.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 184931581 = 307 ⋅602383.

It can be written as a sum of positive squares in 2 ways, for example, as 24255625 + 160883856 = 4925^2 + 12684^2 .

It is a cyclic number.

It is not a de Polignac number, because 185139481 - 2³ = 185139473 is a prime.

It is a super-2 number, since 2×185139481² = 68553254849898722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (185139431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98716 + ... + 100573.

It is an arithmetic number, because the mean of its divisors is an integer number (46334925).

Almost surely, 2^185139481 is an apocalyptic number.

It is an amenable number.

185139481 is a deficient number, since it is larger than the sum of its proper divisors (200219).

185139481 is an equidigital number, since it uses as much as digits as its factorization.

185139481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200218.

The product of its digits is 34560, while the sum is 40.

The square root of 185139481 is about 13606.5969661778. The cubic root of 185139481 is about 569.9450865330.

The spelling of 185139481 in words is "one hundred eighty-five million, one hundred thirty-nine thousand, four hundred eighty-one".