8736721 has 4 divisors (see below), whose sum is σ = 9984832. Its totient is φ = 7488612.

The previous prime is 8736719. The next prime is 8736727. The reversal of 8736721 is 1276378.

8736721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 8736721 - 2¹ = 8736719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8736727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 624045 + ... + 624058.

It is an arithmetic number, because the mean of its divisors is an integer number (2496208).

Almost surely, 2^8736721 is an apocalyptic number.

It is an amenable number.

8736721 is a deficient number, since it is larger than the sum of its proper divisors (1248111).

8736721 is a wasteful number, since it uses less digits than its factorization.

8736721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1248110.

The product of its digits is 14112, while the sum is 34.

The square root of 8736721 is about 2955.7944786470. The cubic root of 8736721 is about 205.9599711710.

The spelling of 8736721 in words is "eight million, seven hundred thirty-six thousand, seven hundred twenty-one".