15909421 has 4 divisors (see below), whose sum is σ = 17355744. Its totient is φ = 14463100.

The previous prime is 15909407. The next prime is 15909427. The reversal of 15909421 is 12490951.

15909421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 15909421 - 2¹³ = 15901229 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15909427) 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, 723145 + ... + 723166.

It is an arithmetic number, because the mean of its divisors is an integer number (4338936).

Almost surely, 2^15909421 is an apocalyptic number.

15909421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

15909421 is a deficient number, since it is larger than the sum of its proper divisors (1446323).

15909421 is a wasteful number, since it uses less digits than its factorization.

15909421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1446322.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 15909421 is about 3988.6615549580. The cubic root of 15909421 is about 251.5077998759.

It can be divided in two parts, 1590 and 9421, that added together give a palindrome (11011).

The spelling of 15909421 in words is "fifteen million, nine hundred nine thousand, four hundred twenty-one".