15291421 has 2 divisors, whose sum is σ = 15291422. Its totient is φ = 15291420.

The previous prime is 15291413. The next prime is 15291427. The reversal of 15291421 is 12419251.

It is a happy number.

15291421 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., 14668900 + 622521 = 3830^2 + 789^2 .

It is a cyclic number.

It is not a de Polignac number, because 15291421 - 2³ = 15291413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15291427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7645710 + 7645711.

It is an arithmetic number, because the mean of its divisors is an integer number (7645711).

Almost surely, 2^15291421 is an apocalyptic number.

It is an amenable number.

15291421 is a deficient number, since it is larger than the sum of its proper divisors (1).

15291421 is an equidigital number, since it uses as much as digits as its factorization.

15291421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 25.

The square root of 15291421 is about 3910.4246572463. The cubic root of 15291421 is about 248.2080990500.

The spelling of 15291421 in words is "fifteen million, two hundred ninety-one thousand, four hundred twenty-one".