2640643433 has 4 divisors (see below), whose sum is σ = 2690466948. Its totient is φ = 2590819920.

The previous prime is 2640643403. The next prime is 2640643451. The reversal of 2640643433 is 3343460462.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3343460462 = 2 ⋅1671730231.

It can be written as a sum of positive squares in 2 ways, for example, as 1808205529 + 832437904 = 42523^2 + 28852^2 .

It is a cyclic number.

It is not a de Polignac number, because 2640643433 - 2¹⁶ = 2640577897 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2640643393 and 2640643402.

It is not an unprimeable number, because it can be changed into a prime (2640643403) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24911678 + ... + 24911783.

It is an arithmetic number, because the mean of its divisors is an integer number (672616737).

Almost surely, 2^2640643433 is an apocalyptic number.

It is an amenable number.

2640643433 is a deficient number, since it is larger than the sum of its proper divisors (49823515).

2640643433 is an equidigital number, since it uses as much as digits as its factorization.

2640643433 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49823514.

The product of its (nonzero) digits is 124416, while the sum is 35.

The square root of 2640643433 is about 51387.1913320820. The cubic root of 2640643433 is about 1382.1969195671.

The spelling of 2640643433 in words is "two billion, six hundred forty million, six hundred forty-three thousand, four hundred thirty-three".