2778790081 has 4 divisors (see below), whose sum is σ = 2782710100. Its totient is φ = 2774870064.

The previous prime is 2778790061. The next prime is 2778790111. The reversal of 2778790081 is 1800978772.

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

It can be written as a sum of positive squares in 2 ways, for example, as 309197056 + 2469593025 = 17584^2 + 49695^2 .

It is a cyclic number.

It is not a de Polignac number, because 2778790081 - 2⁹ = 2778789569 is a prime.

It is a super-2 number, since 2×2778790081² = 15443348628527973122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2778790061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1958946 + ... + 1960363.

It is an arithmetic number, because the mean of its divisors is an integer number (695677525).

Almost surely, 2^2778790081 is an apocalyptic number.

It is an amenable number.

2778790081 is a deficient number, since it is larger than the sum of its proper divisors (3920019).

2778790081 is an equidigital number, since it uses as much as digits as its factorization.

2778790081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3920018.

The product of its (nonzero) digits is 395136, while the sum is 49.

The square root of 2778790081 is about 52714.2303462737. The cubic root of 2778790081 is about 1405.8918500179.

The spelling of 2778790081 in words is "two billion, seven hundred seventy-eight million, seven hundred ninety thousand, eighty-one".