643040036401 has 12 divisors (see below), whose sum is σ = 760288892340. Its totient is φ = 542141480160.

The previous prime is 643040036399. The next prime is 643040036423. The reversal of 643040036401 is 104630040346.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 203650028176 + 439390008225 = 451276^2 + 662865^2 .

It is not a de Polignac number, because 643040036401 - 2¹ = 643040036399 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643040036491) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 107564766 + ... + 107570743.

It is an arithmetic number, because the mean of its divisors is an integer number (63357407695).

Almost surely, 2^643040036401 is an apocalyptic number.

643040036401 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

643040036401 is a deficient number, since it is larger than the sum of its proper divisors (117248855939).

643040036401 is a wasteful number, since it uses less digits than its factorization.

643040036401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215135584 (or 215135577 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 31.

Adding to 643040036401 its reverse (104630040346), we get a palindrome (747670076747).

The spelling of 643040036401 in words is "six hundred forty-three billion, forty million, thirty-six thousand, four hundred one".