6661404137 has 2 divisors, whose sum is σ = 6661404138. Its totient is φ = 6661404136.

The previous prime is 6661404077. The next prime is 6661404149. The reversal of 6661404137 is 7314041666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4206300736 + 2455103401 = 64856^2 + 49549^2 .

It is a cyclic number.

It is not a de Polignac number, because 6661404137 - 2⁶ = 6661404073 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6661404137.

It is not a weakly prime, because it can be changed into another prime (6661404157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3330702068 + 3330702069.

It is an arithmetic number, because the mean of its divisors is an integer number (3330702069).

Almost surely, 2^6661404137 is an apocalyptic number.

It is an amenable number.

6661404137 is a deficient number, since it is larger than the sum of its proper divisors (1).

6661404137 is an equidigital number, since it uses as much as digits as its factorization.

6661404137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 38.

The square root of 6661404137 is about 81617.4254494713. The cubic root of 6661404137 is about 1881.5767043967.

The spelling of 6661404137 in words is "six billion, six hundred sixty-one million, four hundred four thousand, one hundred thirty-seven".