87305721 has 8 divisors (see below), whose sum is σ = 117438240. Its totient is φ = 57688512.

The previous prime is 87305719. The next prime is 87305731. The reversal of 87305721 is 12750378.

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

It is not a de Polignac number, because 87305721 - 2¹ = 87305719 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (87305711) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 128431 + ... + 129108.

It is an arithmetic number, because the mean of its divisors is an integer number (14679780).

Almost surely, 2^87305721 is an apocalyptic number.

It is an amenable number.

87305721 is a deficient number, since it is larger than the sum of its proper divisors (30132519).

87305721 is a wasteful number, since it uses less digits than its factorization.

87305721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257655.

The product of its (nonzero) digits is 11760, while the sum is 33.

The square root of 87305721 is about 9343.7530468222. The cubic root of 87305721 is about 443.6231838634.

The spelling of 87305721 in words is "eighty-seven million, three hundred five thousand, seven hundred twenty-one".