6660495778 has 4 divisors (see below), whose sum is σ = 9990743670. Its totient is φ = 3330247888.

The previous prime is 6660495727. The next prime is 6660495791. The reversal of 6660495778 is 8775940666.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 5190770209 + 1469725569 = 72047^2 + 38337^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1665123943 + ... + 1665123946.

Almost surely, 2^6660495778 is an apocalyptic number.

6660495778 is a deficient number, since it is larger than the sum of its proper divisors (3330247892).

6660495778 is a wasteful number, since it uses less digits than its factorization.

6660495778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3330247891.

The product of its (nonzero) digits is 15240960, while the sum is 58.

The square root of 6660495778 is about 81611.8605228431. The cubic root of 6660495778 is about 1881.4911756407.

The spelling of 6660495778 in words is "six billion, six hundred sixty million, four hundred ninety-five thousand, seven hundred seventy-eight".