428687621 has 2 divisors, whose sum is σ = 428687622. Its totient is φ = 428687620.

The previous prime is 428687603. The next prime is 428687627. The reversal of 428687621 is 126786824.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 371140225 + 57547396 = 19265^2 + 7586^2 .

It is a cyclic number.

It is not a de Polignac number, because 428687621 - 2¹⁴ = 428671237 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 (428687627) 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, 214343810 + 214343811.

It is an arithmetic number, because the mean of its divisors is an integer number (214343811).

Almost surely, 2^428687621 is an apocalyptic number.

It is an amenable number.

428687621 is a deficient number, since it is larger than the sum of its proper divisors (1).

428687621 is an equidigital number, since it uses as much as digits as its factorization.

428687621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 258048, while the sum is 44.

The square root of 428687621 is about 20704.7729038500. The cubic root of 428687621 is about 754.0155706269.

The spelling of 428687621 in words is "four hundred twenty-eight million, six hundred eighty-seven thousand, six hundred twenty-one".