2640435209 has 2 divisors, whose sum is σ = 2640435210. Its totient is φ = 2640435208.

The previous prime is 2640435197. The next prime is 2640435211. The reversal of 2640435209 is 9025340462.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1730809609 + 909625600 = 41603^2 + 30160^2 .

It is a cyclic number.

It is not a de Polignac number, because 2640435209 - 2¹² = 2640431113 is a prime.

Together with 2640435211, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2640435269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1320217604 + 1320217605.

It is an arithmetic number, because the mean of its divisors is an integer number (1320217605).

Almost surely, 2^2640435209 is an apocalyptic number.

It is an amenable number.

2640435209 is a deficient number, since it is larger than the sum of its proper divisors (1).

2640435209 is an equidigital number, since it uses as much as digits as its factorization.

2640435209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 35.

The square root of 2640435209 is about 51385.1652619703. The cubic root of 2640435209 is about 1382.1605882531.

The spelling of 2640435209 in words is "two billion, six hundred forty million, four hundred thirty-five thousand, two hundred nine".