421216409 has 2 divisors, whose sum is σ = 421216410. Its totient is φ = 421216408.

The previous prime is 421216391. The next prime is 421216423. The reversal of 421216409 is 904612124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 406224025 + 14992384 = 20155^2 + 3872^2 .

It is a cyclic number.

It is not a de Polignac number, because 421216409 - 2⁸ = 421216153 is a prime.

It is not a weakly prime, because it can be changed into another prime (421216459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210608204 + 210608205.

It is an arithmetic number, because the mean of its divisors is an integer number (210608205).

Almost surely, 2^421216409 is an apocalyptic number.

It is an amenable number.

421216409 is a deficient number, since it is larger than the sum of its proper divisors (1).

421216409 is an equidigital number, since it uses as much as digits as its factorization.

421216409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 421216409 is about 20523.5574158088. The cubic root of 421216409 is about 749.6095205882.

The spelling of 421216409 in words is "four hundred twenty-one million, two hundred sixteen thousand, four hundred nine".