6660400939 has 2 divisors, whose sum is σ = 6660400940. Its totient is φ = 6660400938.

The previous prime is 6660400931. The next prime is 6660400993. The reversal of 6660400939 is 9390040666.

Together with next prime (6660400993) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6660400939 - 2³ = 6660400931 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 6660400895 and 6660400904.

It is not a weakly prime, because it can be changed into another prime (6660400931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3330200469 + 3330200470.

It is an arithmetic number, because the mean of its divisors is an integer number (3330200470).

Almost surely, 2^6660400939 is an apocalyptic number.

6660400939 is a deficient number, since it is larger than the sum of its proper divisors (1).

6660400939 is an equidigital number, since it uses as much as digits as its factorization.

6660400939 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 209952, while the sum is 43.

The square root of 6660400939 is about 81611.2794839047. The cubic root of 6660400939 is about 1881.4822453951.

The spelling of 6660400939 in words is "six billion, six hundred sixty million, four hundred thousand, nine hundred thirty-nine".