649667809 has 8 divisors (see below), whose sum is σ = 751423680. Its totient is φ = 550148496.

The previous prime is 649667803. The next prime is 649667827. The reversal of 649667809 is 908766946.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 649667809 - 2²¹ = 647570657 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 649667809.

It is not an unprimeable number, because it can be changed into a prime (649667803) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 558514 + ... + 559675.

It is an arithmetic number, because the mean of its divisors is an integer number (93927960).

Almost surely, 2^649667809 is an apocalyptic number.

It is an amenable number.

649667809 is a deficient number, since it is larger than the sum of its proper divisors (101755871).

649667809 is a wasteful number, since it uses less digits than its factorization.

649667809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1118279.

The product of its (nonzero) digits is 3919104, while the sum is 55.

The square root of 649667809 is about 25488.5819338778. The cubic root of 649667809 is about 866.0915125875.

It can be divided in two parts, 6496 and 67809, that added together give a triangular number (74305 = T₃₈₅).

The spelling of 649667809 in words is "six hundred forty-nine million, six hundred sixty-seven thousand, eight hundred nine".