285661921 has 8 divisors (see below), whose sum is σ = 290695680. Its totient is φ = 280658592.

The previous prime is 285661907. The next prime is 285661969. The reversal of 285661921 is 129166582.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 285661921 - 2⁵ = 285661889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (285661021) 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 7 ways as a sum of consecutive naturals, for example, 11760 + ... + 26638.

It is an arithmetic number, because the mean of its divisors is an integer number (36336960).

Almost surely, 2^285661921 is an apocalyptic number.

It is an amenable number.

285661921 is a deficient number, since it is larger than the sum of its proper divisors (5033759).

285661921 is a wasteful number, since it uses less digits than its factorization.

285661921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15215.

The product of its digits is 51840, while the sum is 40.

The square root of 285661921 is about 16901.5360544537. The cubic root of 285661921 is about 658.5935161867.

The spelling of 285661921 in words is "two hundred eighty-five million, six hundred sixty-one thousand, nine hundred twenty-one".