281040030721 has 4 divisors (see below), whose sum is σ = 297571797252. Its totient is φ = 264508264192.

The previous prime is 281040030673. The next prime is 281040030763. The reversal of 281040030721 is 127030040182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127030040182 = 2 ⋅63515020091.

It can be written as a sum of positive squares in 2 ways, for example, as 208907500096 + 72132530625 = 457064^2 + 268575^2 .

It is a cyclic number.

It is not a de Polignac number, because 281040030721 - 2¹⁷ = 281039899649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 281040030721.

It is not an unprimeable number, because it can be changed into a prime (281040033721) 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, 8265883240 + ... + 8265883273.

It is an arithmetic number, because the mean of its divisors is an integer number (74392949313).

Almost surely, 2^281040030721 is an apocalyptic number.

It is an amenable number.

281040030721 is a deficient number, since it is larger than the sum of its proper divisors (16531766531).

281040030721 is a wasteful number, since it uses less digits than its factorization.

281040030721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16531766530.

The product of its (nonzero) digits is 2688, while the sum is 28.

The spelling of 281040030721 in words is "two hundred eighty-one billion, forty million, thirty thousand, seven hundred twenty-one".