1640342020 has 24 divisors (see below), whose sum is σ = 3448096344. Its totient is φ = 655493376.

The previous prime is 1640341999. The next prime is 1640342021. The reversal of 1640342020 is 202430461.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 335109636 + 1305232384 = 18306^2 + 36128^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1640341982 and 1640342000.

It is not an unprimeable number, because it can be changed into a prime (1640342021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19039 + ... + 60358.

It is an arithmetic number, because the mean of its divisors is an integer number (143670681).

Almost surely, 2^1640342020 is an apocalyptic number.

1640342020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1640342020 is an abundant number, since it is smaller than the sum of its proper divisors (1807754324).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1640342020 is a wasteful number, since it uses less digits than its factorization.

1640342020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80439 (or 80437 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 1640342020 is about 40501.1360334497. The cubic root of 1640342020 is about 1179.3556809938.

Adding to 1640342020 its reverse (202430461), we get a palindrome (1842772481).

The spelling of 1640342020 in words is "one billion, six hundred forty million, three hundred forty-two thousand, twenty".