16042421 has 4 divisors (see below), whose sum is σ = 16099392. Its totient is φ = 15985452.

The previous prime is 16042399. The next prime is 16042427. The reversal of 16042421 is 12424061.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12424061 = 13 ⋅955697.

It is a cyclic number.

It is not a de Polignac number, because 16042421 - 2¹⁰ = 16041397 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16042393 and 16042402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16042427) 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, 28061 + ... + 28626.

It is an arithmetic number, because the mean of its divisors is an integer number (4024848).

Almost surely, 2^16042421 is an apocalyptic number.

It is an amenable number.

16042421 is a deficient number, since it is larger than the sum of its proper divisors (56971).

16042421 is an equidigital number, since it uses as much as digits as its factorization.

16042421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56970.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 16042421 is about 4005.2991149226. The cubic root of 16042421 is about 252.2067097511.

Adding to 16042421 its reverse (12424061), we get a palindrome (28466482).

The spelling of 16042421 in words is "sixteen million, forty-two thousand, four hundred twenty-one".