8791421 has 2 divisors, whose sum is σ = 8791422. Its totient is φ = 8791420.

The previous prime is 8791411. The next prime is 8791423. The reversal of 8791421 is 1241978.

8791421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8791225 + 196 = 2965^2 + 14^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8791421 is a prime.

It is a Sophie Germain prime.

Together with 8791423, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8791423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4395710 + 4395711.

It is an arithmetic number, because the mean of its divisors is an integer number (4395711).

Almost surely, 2^8791421 is an apocalyptic number.

It is an amenable number.

8791421 is a deficient number, since it is larger than the sum of its proper divisors (1).

8791421 is an equidigital number, since it uses as much as digits as its factorization.

8791421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 32.

The square root of 8791421 is about 2965.0330520923. The cubic root of 8791421 is about 206.3889108904.

The spelling of 8791421 in words is "eight million, seven hundred ninety-one thousand, four hundred twenty-one".