7887921 has 4 divisors (see below), whose sum is σ = 10517232. Its totient is φ = 5258612.

The previous prime is 7887889. The next prime is 7887923. The reversal of 7887921 is 1297887.

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 7887921 - 2⁵ = 7887889 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (7887923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1314651 + ... + 1314656.

It is an arithmetic number, because the mean of its divisors is an integer number (2629308).

Almost surely, 2^7887921 is an apocalyptic number.

It is an amenable number.

7887921 is a deficient number, since it is larger than the sum of its proper divisors (2629311).

7887921 is a wasteful number, since it uses less digits than its factorization.

7887921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2629310.

The product of its digits is 56448, while the sum is 42.

The square root of 7887921 is about 2808.5442848565. The cubic root of 7887921 is about 199.0616123625.

The spelling of 7887921 in words is "seven million, eight hundred eighty-seven thousand, nine hundred twenty-one".