281640538 has 8 divisors (see below), whose sum is σ = 429386580. Its totient is φ = 138511680.

The previous prime is 281640533. The next prime is 281640577. The reversal of 281640538 is 835046182.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 235223569 + 46416969 = 15337^2 + 6813^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 281640497 and 281640506.

It is not an unprimeable number, because it can be changed into a prime (281640533) 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, 1154143 + ... + 1154386.

Almost surely, 2^281640538 is an apocalyptic number.

281640538 is a deficient number, since it is larger than the sum of its proper divisors (147746042).

281640538 is a wasteful number, since it uses less digits than its factorization.

281640538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2308592.

The product of its (nonzero) digits is 46080, while the sum is 37.

The square root of 281640538 is about 16782.1493855823. The cubic root of 281640538 is about 655.4884672874.

The spelling of 281640538 in words is "two hundred eighty-one million, six hundred forty thousand, five hundred thirty-eight".