281238813 has 18 divisors (see below), whose sum is σ = 417667614. Its totient is φ = 182226672.

The previous prime is 281238809. The next prime is 281238821. The reversal of 281238813 is 318832182.

It can be written as a sum of positive squares in only one way, i.e., 273637764 + 7601049 = 16542^2 + 2757^2 .

It is not a de Polignac number, because 281238813 - 2² = 281238809 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (281238823) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 305568 + ... + 306486.

Almost surely, 2^281238813 is an apocalyptic number.

It is an amenable number.

281238813 is a deficient number, since it is larger than the sum of its proper divisors (136428801).

281238813 is an frugal number, since it uses more digits than its factorization.

281238813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1881 (or 959 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 281238813 is about 16770.1762960322. The cubic root of 281238813 is about 655.1766615529.

The spelling of 281238813 in words is "two hundred eighty-one million, two hundred thirty-eight thousand, eight hundred thirteen".