643822516 has 6 divisors (see below), whose sum is σ = 1126689410. Its totient is φ = 321911256.

The previous prime is 643822499. The next prime is 643822523. The reversal of 643822516 is 615228346.

It can be written as a sum of positive squares in only one way, i.e., 351412516 + 292410000 = 18746^2 + 17100^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80477811 + ... + 80477818.

Almost surely, 2^643822516 is an apocalyptic number.

It is an amenable number.

643822516 is a deficient number, since it is larger than the sum of its proper divisors (482866894).

643822516 is a wasteful number, since it uses less digits than its factorization.

643822516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160955633 (or 160955631 counting only the distinct ones).

The product of its digits is 69120, while the sum is 37.

The square root of 643822516 is about 25373.6579152475. The cubic root of 643822516 is about 863.4861717487.

The spelling of 643822516 in words is "six hundred forty-three million, eight hundred twenty-two thousand, five hundred sixteen".