208416421 has 2 divisors, whose sum is σ = 208416422. Its totient is φ = 208416420.

The previous prime is 208416389. The next prime is 208416427. The reversal of 208416421 is 124614802.

208416421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 119793025 + 88623396 = 10945^2 + 9414^2 .

It is a cyclic number.

It is not a de Polignac number, because 208416421 - 2⁵ = 208416389 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 208416421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (208416427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104208210 + 104208211.

It is an arithmetic number, because the mean of its divisors is an integer number (104208211).

Almost surely, 2^208416421 is an apocalyptic number.

It is an amenable number.

208416421 is a deficient number, since it is larger than the sum of its proper divisors (1).

208416421 is an equidigital number, since it uses as much as digits as its factorization.

208416421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 208416421 is about 14436.6346840252. The cubic root of 208416421 is about 592.8943493312.

The spelling of 208416421 in words is "two hundred eight million, four hundred sixteen thousand, four hundred twenty-one".