15591421 has 2 divisors, whose sum is σ = 15591422. Its totient is φ = 15591420.

The previous prime is 15591383. The next prime is 15591449. The reversal of 15591421 is 12419551.

It is an a-pointer prime, because the next prime (15591449) can be obtained adding 15591421 to its sum of digits (28).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15327225 + 264196 = 3915^2 + 514^2 .

It is a cyclic number.

It is not a de Polignac number, because 15591421 - 2⁷ = 15591293 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 15591421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15591461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7795710 + 7795711.

It is an arithmetic number, because the mean of its divisors is an integer number (7795711).

Almost surely, 2^15591421 is an apocalyptic number.

It is an amenable number.

15591421 is a deficient number, since it is larger than the sum of its proper divisors (1).

15591421 is an equidigital number, since it uses as much as digits as its factorization.

15591421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1800, while the sum is 28.

The square root of 15591421 is about 3948.5973458939. The cubic root of 15591421 is about 249.8207835566.

The spelling of 15591421 in words is "fifteen million, five hundred ninety-one thousand, four hundred twenty-one".