28157778811 has 4 divisors (see below), whose sum is σ = 28303674232. Its totient is φ = 28011883392.

The previous prime is 28157778799. The next prime is 28157778823. The reversal of 28157778811 is 11887775182.

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

It is an interprime number because it is at equal distance from previous prime (28157778799) and next prime (28157778823).

It is a cyclic number.

It is not a de Polignac number, because 28157778811 - 2⁷ = 28157778683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28157748811) 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, 72947421 + ... + 72947806.

It is an arithmetic number, because the mean of its divisors is an integer number (7075918558).

Almost surely, 2^28157778811 is an apocalyptic number.

28157778811 is a deficient number, since it is larger than the sum of its proper divisors (145895421).

28157778811 is a wasteful number, since it uses less digits than its factorization.

28157778811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145895420.

The product of its digits is 1756160, while the sum is 55.

The spelling of 28157778811 in words is "twenty-eight billion, one hundred fifty-seven million, seven hundred seventy-eight thousand, eight hundred eleven".