620728709 has 4 divisors (see below), whose sum is σ = 629231916. Its totient is φ = 612225504.

The previous prime is 620728699. The next prime is 620728781. The reversal of 620728709 is 907827026.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 379392484 + 241336225 = 19478^2 + 15535^2 .

It is a cyclic number.

It is not a de Polignac number, because 620728709 - 2²⁰ = 619680133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (620788709) 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, 4251494 + ... + 4251639.

It is an arithmetic number, because the mean of its divisors is an integer number (157307979).

Almost surely, 2^620728709 is an apocalyptic number.

It is an amenable number.

620728709 is a deficient number, since it is larger than the sum of its proper divisors (8503207).

620728709 is an equidigital number, since it uses as much as digits as its factorization.

620728709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8503206.

The product of its (nonzero) digits is 84672, while the sum is 41.

The square root of 620728709 is about 24914.4277277244. The cubic root of 620728709 is about 853.0358382562.

The spelling of 620728709 in words is "six hundred twenty million, seven hundred twenty-eight thousand, seven hundred nine".