646838986 has 8 divisors (see below), whose sum is σ = 971008164. Its totient is φ = 323169600.

The previous prime is 646838923. The next prime is 646838993. The reversal of 646838986 is 689838646.

It can be written as a sum of positive squares in 2 ways, for example, as 442892025 + 203946961 = 21045^2 + 14281^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 646838986.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121695 + ... + 126898.

Almost surely, 2^646838986 is an apocalyptic number.

646838986 is a deficient number, since it is larger than the sum of its proper divisors (324169178).

646838986 is a wasteful number, since it uses less digits than its factorization.

646838986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249896.

The product of its digits is 11943936, while the sum is 58.

The square root of 646838986 is about 25433.0294302507. The cubic root of 646838986 is about 864.8326208933.

It can be divided in two parts, 6468 and 38986, that added together give a palindrome (45454).

The spelling of 646838986 in words is "six hundred forty-six million, eight hundred thirty-eight thousand, nine hundred eighty-six".