2778891556609 has 8 divisors (see below), whose sum is σ = 3176002708928. Its totient is φ = 2381812065360.

The previous prime is 2778891556603. The next prime is 2778891556613. The reversal of 2778891556609 is 9066551988772.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2778891556609 - 2⁵ = 2778891556577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2778891556603) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7726887 + ... + 8078524.

It is an arithmetic number, because the mean of its divisors is an integer number (397000338616).

Almost surely, 2^{2778891556609} is an apocalyptic number.

It is an amenable number.

2778891556609 is a deficient number, since it is larger than the sum of its proper divisors (397111152319).

2778891556609 is a wasteful number, since it uses less digits than its factorization.

2778891556609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15830535.

The product of its (nonzero) digits is 457228800, while the sum is 73.

The spelling of 2778891556609 in words is "two trillion, seven hundred seventy-eight billion, eight hundred ninety-one million, five hundred fifty-six thousand, six hundred nine".