281220138 has 12 divisors (see below), whose sum is σ = 609310338. Its totient is φ = 93740040.

The previous prime is 281220073. The next prime is 281220143. The reversal of 281220138 is 831022182.

It can be written as a sum of positive squares in only one way, i.e., 181360089 + 99860049 = 13467^2 + 9993^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7811653 + ... + 7811688.

Almost surely, 2^281220138 is an apocalyptic number.

281220138 is an abundant number, since it is smaller than the sum of its proper divisors (328090200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

281220138 is a wasteful number, since it uses less digits than its factorization.

281220138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15623349 (or 15623346 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 281220138 is about 16769.6194947888. The cubic root of 281220138 is about 655.1621594116.

The spelling of 281220138 in words is "two hundred eighty-one million, two hundred twenty thousand, one hundred thirty-eight".