628426509 has 4 divisors (see below), whose sum is σ = 837902016. Its totient is φ = 418951004.

The previous prime is 628426457. The next prime is 628426517. The reversal of 628426509 is 905624826.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 628426509 - 2⁹ = 628425997 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (628406509) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104737749 + ... + 104737754.

It is an arithmetic number, because the mean of its divisors is an integer number (209475504).

Almost surely, 2^628426509 is an apocalyptic number.

It is an amenable number.

628426509 is a deficient number, since it is larger than the sum of its proper divisors (209475507).

628426509 is a wasteful number, since it uses less digits than its factorization.

628426509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209475506.

The product of its (nonzero) digits is 207360, while the sum is 42.

The square root of 628426509 is about 25068.4365088850. The cubic root of 628426509 is about 856.5475927669.

The spelling of 628426509 in words is "six hundred twenty-eight million, four hundred twenty-six thousand, five hundred nine".