16213421 has 4 divisors (see below), whose sum is σ = 18529632. Its totient is φ = 13897212.

The previous prime is 16213411. The next prime is 16213433. The reversal of 16213421 is 12431261.

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 not a de Polignac number, because 16213421 - 2¹⁸ = 15951277 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16213393 and 16213402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16213411) 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, 1158095 + ... + 1158108.

It is an arithmetic number, because the mean of its divisors is an integer number (4632408).

Almost surely, 2^16213421 is an apocalyptic number.

It is an amenable number.

16213421 is a deficient number, since it is larger than the sum of its proper divisors (2316211).

16213421 is an equidigital number, since it uses as much as digits as its factorization.

16213421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2316210.

The product of its digits is 288, while the sum is 20.

The square root of 16213421 is about 4026.5892514633. The cubic root of 16213421 is about 253.0996550552.

Adding to 16213421 its reverse (12431261), we get a palindrome (28644682).

The spelling of 16213421 in words is "sixteen million, two hundred thirteen thousand, four hundred twenty-one".