280138665 has 32 divisors (see below), whose sum is σ = 481303296. Its totient is φ = 138629120.

The previous prime is 280138633. The next prime is 280138669. The reversal of 280138665 is 566831082.

It is a happy number.

It is not a de Polignac number, because 280138665 - 2⁵ = 280138633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (280138669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10369 + ... + 25841.

It is an arithmetic number, because the mean of its divisors is an integer number (15040728).

Almost surely, 2^280138665 is an apocalyptic number.

It is an amenable number.

280138665 is a deficient number, since it is larger than the sum of its proper divisors (201164631).

280138665 is a wasteful number, since it uses less digits than its factorization.

280138665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15569.

The product of its (nonzero) digits is 69120, while the sum is 39.

The square root of 280138665 is about 16737.3434271990. The cubic root of 280138665 is about 654.3212400268.

The spelling of 280138665 in words is "two hundred eighty million, one hundred thirty-eight thousand, six hundred sixty-five".