1640688068 has 6 divisors (see below), whose sum is σ = 2871204126. Its totient is φ = 820344032.

The previous prime is 1640688061. The next prime is 1640688083. The reversal of 1640688068 is 8608860461.

It can be written as a sum of positive squares in only one way, i.e., 1366189444 + 274498624 = 36962^2 + 16568^2 .

It is not an unprimeable number, because it can be changed into a prime (1640688061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 205086005 + ... + 205086012.

It is an arithmetic number, because the mean of its divisors is an integer number (478534021).

Almost surely, 2^1640688068 is an apocalyptic number.

It is an amenable number.

1640688068 is a deficient number, since it is larger than the sum of its proper divisors (1230516058).

1640688068 is a wasteful number, since it uses less digits than its factorization.

1640688068 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410172021 (or 410172019 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 47.

The square root of 1640688068 is about 40505.4078858614. The cubic root of 1640688068 is about 1179.4386078010.

The spelling of 1640688068 in words is "one billion, six hundred forty million, six hundred eighty-eight thousand, sixty-eight".