15315421 has 4 divisors (see below), whose sum is σ = 16707744. Its totient is φ = 13923100.

The previous prime is 15315389. The next prime is 15315431. The reversal of 15315421 is 12451351.

It is a happy number.

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 15315421 - 2⁵ = 15315389 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15315392 and 15315401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15315431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 696145 + ... + 696166.

It is an arithmetic number, because the mean of its divisors is an integer number (4176936).

Almost surely, 2^15315421 is an apocalyptic number.

15315421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

15315421 is a deficient number, since it is larger than the sum of its proper divisors (1392323).

15315421 is a wasteful number, since it uses less digits than its factorization.

15315421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1392322.

The product of its digits is 600, while the sum is 22.

The square root of 15315421 is about 3913.4921745163. The cubic root of 15315421 is about 248.3378859977.

Adding to 15315421 its reverse (12451351), we get a palindrome (27766772).

The spelling of 15315421 in words is "fifteen million, three hundred fifteen thousand, four hundred twenty-one".