646831009 has 4 divisors (see below), whose sum is σ = 705633840. Its totient is φ = 588028180.

The previous prime is 646830991. The next prime is 646831013. The reversal of 646831009 is 900138646.

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 646831009 - 2¹¹ = 646828961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646831099) 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, 29401399 + ... + 29401420.

It is an arithmetic number, because the mean of its divisors is an integer number (176408460).

Almost surely, 2^646831009 is an apocalyptic number.

It is an amenable number.

646831009 is a deficient number, since it is larger than the sum of its proper divisors (58802831).

646831009 is a wasteful number, since it uses less digits than its factorization.

646831009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58802830.

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 646831009 is about 25432.8726061371. The cubic root of 646831009 is about 864.8290657592.

The spelling of 646831009 in words is "six hundred forty-six million, eight hundred thirty-one thousand, nine".