15421729 has 2 divisors, whose sum is σ = 15421730. Its totient is φ = 15421728.

The previous prime is 15421727. The next prime is 15421759. The reversal of 15421729 is 92712451.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15421329 + 400 = 3927^2 + 20^2 .

It is a cyclic number.

It is not a de Polignac number, because 15421729 - 2¹ = 15421727 is a prime.

Together with 15421727, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 15421729.

It is not a weakly prime, because it can be changed into another prime (15421723) 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 as a sum of consecutive naturals, namely, 7710864 + 7710865.

It is an arithmetic number, because the mean of its divisors is an integer number (7710865).

Almost surely, 2^15421729 is an apocalyptic number.

It is an amenable number.

15421729 is a deficient number, since it is larger than the sum of its proper divisors (1).

15421729 is an equidigital number, since it uses as much as digits as its factorization.

15421729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5040, while the sum is 31.

The square root of 15421729 is about 3927.0509291324. The cubic root of 15421729 is about 248.9111525297.

The spelling of 15421729 in words is "fifteen million, four hundred twenty-one thousand, seven hundred twenty-nine".