15406421 has 4 divisors (see below), whose sum is σ = 15422700. Its totient is φ = 15390144.

The previous prime is 15406399. The next prime is 15406429. The reversal of 15406421 is 12460451.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12460451 = 613 ⋅20327.

It can be written as a sum of positive squares in 2 ways, for example, as 5827396 + 9579025 = 2414^2 + 3095^2 .

It is a cyclic number.

It is not a de Polignac number, because 15406421 - 2⁶ = 15406357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15406429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6626 + ... + 8643.

It is an arithmetic number, because the mean of its divisors is an integer number (3855675).

Almost surely, 2^15406421 is an apocalyptic number.

It is an amenable number.

15406421 is a deficient number, since it is larger than the sum of its proper divisors (16279).

15406421 is a wasteful number, since it uses less digits than its factorization.

15406421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16278.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 15406421 is about 3925.1013999641. The cubic root of 15406421 is about 248.8287667530.

Adding to 15406421 its reverse (12460451), we get a palindrome (27866872).

The spelling of 15406421 in words is "fifteen million, four hundred six thousand, four hundred twenty-one".