7871921 has 4 divisors (see below), whose sum is σ = 7932144. Its totient is φ = 7811700.

The previous prime is 7871917. The next prime is 7871933. The reversal of 7871921 is 1291787.

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 7871921 - 2² = 7871917 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (7871971) 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, 29915 + ... + 30176.

It is an arithmetic number, because the mean of its divisors is an integer number (1983036).

Almost surely, 2^7871921 is an apocalyptic number.

It is an amenable number.

7871921 is a deficient number, since it is larger than the sum of its proper divisors (60223).

7871921 is a wasteful number, since it uses less digits than its factorization.

7871921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60222.

The product of its digits is 7056, while the sum is 35.

The square root of 7871921 is about 2805.6943882041. The cubic root of 7871921 is about 198.9269278780.

The spelling of 7871921 in words is "seven million, eight hundred seventy-one thousand, nine hundred twenty-one".