281630138 has 4 divisors (see below), whose sum is σ = 422445210. Its totient is φ = 140815068.

The previous prime is 281630137. The next prime is 281630171. The reversal of 281630138 is 831036182.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 281467729 + 162409 = 16777^2 + 403^2 .

It is not an unprimeable number, because it can be changed into a prime (281630137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 70407533 + ... + 70407536.

Almost surely, 2^281630138 is an apocalyptic number.

281630138 is a deficient number, since it is larger than the sum of its proper divisors (140815072).

281630138 is a wasteful number, since it uses less digits than its factorization.

281630138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140815071.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 281630138 is about 16781.8395296821. The cubic root of 281630138 is about 655.4803988892.

The spelling of 281630138 in words is "two hundred eighty-one million, six hundred thirty thousand, one hundred thirty-eight".