6619840261 has 2 divisors, whose sum is σ = 6619840262. Its totient is φ = 6619840260.

The previous prime is 6619840259. The next prime is 6619840301. The reversal of 6619840261 is 1620489166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5534467236 + 1085373025 = 74394^2 + 32945^2 .

It is a cyclic number.

It is not a de Polignac number, because 6619840261 - 2¹ = 6619840259 is a prime.

Together with 6619840259, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6619840961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3309920130 + 3309920131.

It is an arithmetic number, because the mean of its divisors is an integer number (3309920131).

Almost surely, 2^6619840261 is an apocalyptic number.

It is an amenable number.

6619840261 is a deficient number, since it is larger than the sum of its proper divisors (1).

6619840261 is an equidigital number, since it uses as much as digits as its factorization.

6619840261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 43.

The square root of 6619840261 is about 81362.4007819337. The cubic root of 6619840261 is about 1877.6551667234.

The spelling of 6619840261 in words is "six billion, six hundred nineteen million, eight hundred forty thousand, two hundred sixty-one".