16672421 has 2 divisors, whose sum is σ = 16672422. Its totient is φ = 16672420.

The previous prime is 16672417. The next prime is 16672423. The reversal of 16672421 is 12427661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8916196 + 7756225 = 2986^2 + 2785^2 .

It is an emirp because it is prime and its reverse (12427661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16672421 - 2² = 16672417 is a prime.

Together with 16672423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16672423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8336210 + 8336211.

It is an arithmetic number, because the mean of its divisors is an integer number (8336211).

Almost surely, 2^16672421 is an apocalyptic number.

It is an amenable number.

16672421 is a deficient number, since it is larger than the sum of its proper divisors (1).

16672421 is an equidigital number, since it uses as much as digits as its factorization.

16672421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 29.

The square root of 16672421 is about 4083.1876028417. The cubic root of 16672421 is about 255.4658714147.

The spelling of 16672421 in words is "sixteen million, six hundred seventy-two thousand, four hundred twenty-one".