16626421 has 4 divisors (see below), whose sum is σ = 19001632. Its totient is φ = 14251212.

The previous prime is 16626403. The next prime is 16626427. The reversal of 16626421 is 12462661.

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: 12462661 = 47 ⋅265163.

It is a cyclic number.

It is not a de Polignac number, because 16626421 - 2⁷ = 16626293 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16626421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16626427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1187595 + ... + 1187608.

It is an arithmetic number, because the mean of its divisors is an integer number (4750408).

Almost surely, 2^16626421 is an apocalyptic number.

It is an amenable number.

16626421 is a deficient number, since it is larger than the sum of its proper divisors (2375211).

16626421 is an equidigital number, since it uses as much as digits as its factorization.

16626421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2375210.

The product of its digits is 3456, while the sum is 28.

The square root of 16626421 is about 4077.5508580519. The cubic root of 16626421 is about 255.2307075220.

The spelling of 16626421 in words is "sixteen million, six hundred twenty-six thousand, four hundred twenty-one".