2758378666 has 4 divisors (see below), whose sum is σ = 4137568002. Its totient is φ = 1379189332.

The previous prime is 2758378633. The next prime is 2758378681. The reversal of 2758378666 is 6668738572.

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., 2755725025 + 2653641 = 52495^2 + 1629^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 2758378666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 689594665 + ... + 689594668.

Almost surely, 2^2758378666 is an apocalyptic number.

2758378666 is a deficient number, since it is larger than the sum of its proper divisors (1379189336).

2758378666 is a wasteful number, since it uses less digits than its factorization.

2758378666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1379189335.

The product of its digits is 20321280, while the sum is 58.

The square root of 2758378666 is about 52520.2690967973. The cubic root of 2758378666 is about 1402.4410925062.

The spelling of 2758378666 in words is "two billion, seven hundred fifty-eight million, three hundred seventy-eight thousand, six hundred sixty-six".