649239805 has 12 divisors (see below), whose sum is σ = 786120660. Its totient is φ = 514744832.

The previous prime is 649239803. The next prime is 649239847. The reversal of 649239805 is 508932946.

It can be written as a sum of positive squares in 6 ways, for example, as 127848249 + 521391556 = 11307^2 + 22834^2 .

It is not a de Polignac number, because 649239805 - 2¹ = 649239803 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649239803) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 58761 + ... + 68929.

It is an arithmetic number, because the mean of its divisors is an integer number (65510055).

Almost surely, 2^649239805 is an apocalyptic number.

It is an amenable number.

649239805 is a deficient number, since it is larger than the sum of its proper divisors (136880855).

649239805 is a wasteful number, since it uses less digits than its factorization.

649239805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10400 (or 10287 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 46.

The square root of 649239805 is about 25480.1845558465. The cubic root of 649239805 is about 865.9012758436.

The spelling of 649239805 in words is "six hundred forty-nine million, two hundred thirty-nine thousand, eight hundred five".