421544309 has 2 divisors, whose sum is σ = 421544310. Its totient is φ = 421544308.

The previous prime is 421544303. The next prime is 421544341. The reversal of 421544309 is 903445124.

It is an a-pointer prime, because the next prime (421544341) can be obtained adding 421544309 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 339370084 + 82174225 = 18422^2 + 9065^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421544309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (421544303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210772154 + 210772155.

It is an arithmetic number, because the mean of its divisors is an integer number (210772155).

Almost surely, 2^421544309 is an apocalyptic number.

It is an amenable number.

421544309 is a deficient number, since it is larger than the sum of its proper divisors (1).

421544309 is an equidigital number, since it uses as much as digits as its factorization.

421544309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 421544309 is about 20531.5442429448. The cubic root of 421544309 is about 749.8039837376.

The spelling of 421544309 in words is "four hundred twenty-one million, five hundred forty-four thousand, three hundred nine".