87172182721 has 16 divisors (see below), whose sum is σ = 94483247040. Its totient is φ = 79947933120.

The previous prime is 87172182707. The next prime is 87172182731. The reversal of 87172182721 is 12728127178.

It is a cyclic number.

It is not a de Polignac number, because 87172182721 - 2⁷ = 87172182593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (87172182731) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12415950 + ... + 12422968.

It is an arithmetic number, because the mean of its divisors is an integer number (5905202940).

Almost surely, 2^87172182721 is an apocalyptic number.

It is an amenable number.

87172182721 is a deficient number, since it is larger than the sum of its proper divisors (7311064319).

87172182721 is a wasteful number, since it uses less digits than its factorization.

87172182721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13056.

The product of its digits is 175616, while the sum is 46.

The spelling of 87172182721 in words is "eighty-seven billion, one hundred seventy-two million, one hundred eighty-two thousand, seven hundred twenty-one".