8632721 has 4 divisors (see below), whose sum is σ = 8653092. Its totient is φ = 8612352.

The previous prime is 8632717. The next prime is 8632727. The reversal of 8632721 is 1272368.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1234321 + 7398400 = 1111^2 + 2720^2 .

It is a cyclic number.

It is not a de Polignac number, because 8632721 - 2² = 8632717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8632727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9536 + ... + 10401.

It is an arithmetic number, because the mean of its divisors is an integer number (2163273).

Almost surely, 2^8632721 is an apocalyptic number.

It is an amenable number.

8632721 is a deficient number, since it is larger than the sum of its proper divisors (20371).

8632721 is a wasteful number, since it uses less digits than its factorization.

8632721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20370.

The product of its digits is 4032, while the sum is 29.

The square root of 8632721 is about 2938.1492474005. The cubic root of 8632721 is about 205.1394728051.

The spelling of 8632721 in words is "eight million, six hundred thirty-two thousand, seven hundred twenty-one".