8731921 has 8 divisors (see below), whose sum is σ = 9576000. Its totient is φ = 7896240.

The previous prime is 8731913. The next prime is 8731937. The reversal of 8731921 is 1291378.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 8731921 - 2³ = 8731913 is a prime.

It is a super-3 number, since 3×8731921³ (a number of 22 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8731901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 195 + ... + 4183.

It is an arithmetic number, because the mean of its divisors is an integer number (1197000).

Almost surely, 2^8731921 is an apocalyptic number.

It is an amenable number.

8731921 is a deficient number, since it is larger than the sum of its proper divisors (844079).

8731921 is a wasteful number, since it uses less digits than its factorization.

8731921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4199.

The product of its digits is 3024, while the sum is 31.

The square root of 8731921 is about 2954.9824026549. The cubic root of 8731921 is about 205.9222457679.

The spelling of 8731921 in words is "eight million, seven hundred thirty-one thousand, nine hundred twenty-one".