8722721 has 4 divisors (see below), whose sum is σ = 9968832. Its totient is φ = 7476612.

The previous prime is 8722711. The next prime is 8722739. The reversal of 8722721 is 1272278.

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 8722721 - 2¹⁴ = 8706337 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8722711) 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, 623045 + ... + 623058.

It is an arithmetic number, because the mean of its divisors is an integer number (2492208).

Almost surely, 2^8722721 is an apocalyptic number.

It is an amenable number.

8722721 is a deficient number, since it is larger than the sum of its proper divisors (1246111).

8722721 is a wasteful number, since it uses less digits than its factorization.

8722721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1246110.

The product of its digits is 3136, while the sum is 29.

The square root of 8722721 is about 2953.4252995463. The cubic root of 8722721 is about 205.8499000837.

Adding to 8722721 its reverse (1272278), we get a palindrome (9994999).

The spelling of 8722721 in words is "eight million, seven hundred twenty-two thousand, seven hundred twenty-one".