428621309 has 2 divisors, whose sum is σ = 428621310. Its totient is φ = 428621308.

The previous prime is 428621299. The next prime is 428621327. The reversal of 428621309 is 903126824.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 407918809 + 20702500 = 20197^2 + 4550^2 .

It is a cyclic number.

It is not a de Polignac number, because 428621309 - 2²⁴ = 411844093 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (428621359) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 214310654 + 214310655.

It is an arithmetic number, because the mean of its divisors is an integer number (214310655).

Almost surely, 2^428621309 is an apocalyptic number.

It is an amenable number.

428621309 is a deficient number, since it is larger than the sum of its proper divisors (1).

428621309 is an equidigital number, since it uses as much as digits as its factorization.

428621309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 428621309 is about 20703.1714720233. The cubic root of 428621309 is about 753.9766900556.

The spelling of 428621309 in words is "four hundred twenty-eight million, six hundred twenty-one thousand, three hundred nine".