6610421861 has 2 divisors, whose sum is σ = 6610421862. Its totient is φ = 6610421860.

The previous prime is 6610421833. The next prime is 6610421911. The reversal of 6610421861 is 1681240166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6157540900 + 452880961 = 78470^2 + 21281^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6610421861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6610481861) 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 as a sum of consecutive naturals, namely, 3305210930 + 3305210931.

It is an arithmetic number, because the mean of its divisors is an integer number (3305210931).

Almost surely, 2^6610421861 is an apocalyptic number.

It is an amenable number.

6610421861 is a deficient number, since it is larger than the sum of its proper divisors (1).

6610421861 is an equidigital number, since it uses as much as digits as its factorization.

6610421861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 6610421861 is about 81304.5008655732. The cubic root of 6610421861 is about 1876.7642640098.

The spelling of 6610421861 in words is "six billion, six hundred ten million, four hundred twenty-one thousand, eight hundred sixty-one".