281705985 has 32 divisors (see below), whose sum is σ = 546341760. Its totient is φ = 136584000.

The previous prime is 281705969. The next prime is 281705993. The reversal of 281705985 is 589507182.

It is a happy number.

It is not a de Polignac number, because 281705985 - 2⁴ = 281705969 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 281705985.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 93366 + ... + 96335.

It is an arithmetic number, because the mean of its divisors is an integer number (17073180).

Almost surely, 2^281705985 is an apocalyptic number.

It is an amenable number.

281705985 is a deficient number, since it is larger than the sum of its proper divisors (264635775).

281705985 is a wasteful number, since it uses less digits than its factorization.

281705985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189726 (or 189720 counting only the distinct ones).

The product of its (nonzero) digits is 201600, while the sum is 45.

The square root of 281705985 is about 16784.0991715373. The cubic root of 281705985 is about 655.5392370043.

It can be divided in two parts, 281 and 705985, that added together give a triangular number (706266 = T₁₁₈₈).

The spelling of 281705985 in words is "two hundred eighty-one million, seven hundred five thousand, nine hundred eighty-five".