8651921 has 4 divisors (see below), whose sum is σ = 8657844. Its totient is φ = 8646000.

The previous prime is 8651917. The next prime is 8651939. The reversal of 8651921 is 1291568.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 4494400 + 4157521 = 2120^2 + 2039^2 .

It is a cyclic number.

It is not a de Polignac number, because 8651921 - 2² = 8651917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8651941) 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, 971 + ... + 4271.

It is an arithmetic number, because the mean of its divisors is an integer number (2164461).

Almost surely, 2^8651921 is an apocalyptic number.

It is an amenable number.

8651921 is a deficient number, since it is larger than the sum of its proper divisors (5923).

8651921 is a wasteful number, since it uses less digits than its factorization.

8651921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5922.

The product of its digits is 4320, while the sum is 32.

The square root of 8651921 is about 2941.4147956383. The cubic root of 8651921 is about 205.2914434866.

The spelling of 8651921 in words is "eight million, six hundred fifty-one thousand, nine hundred twenty-one".