16207421 has 2 divisors, whose sum is σ = 16207422. Its totient is φ = 16207420.

The previous prime is 16207393. The next prime is 16207459. The reversal of 16207421 is 12470261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15888196 + 319225 = 3986^2 + 565^2 .

It is a cyclic number.

It is not a de Polignac number, because 16207421 - 2⁶ = 16207357 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16207921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8103710 + 8103711.

It is an arithmetic number, because the mean of its divisors is an integer number (8103711).

Almost surely, 2^16207421 is an apocalyptic number.

It is an amenable number.

16207421 is a deficient number, since it is larger than the sum of its proper divisors (1).

16207421 is an equidigital number, since it uses as much as digits as its factorization.

16207421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 16207421 is about 4025.8441350852. The cubic root of 16207421 is about 253.0684301974.

Adding to 16207421 its reverse (12470261), we get a palindrome (28677682).

The spelling of 16207421 in words is "sixteen million, two hundred seven thousand, four hundred twenty-one".