28078733861 has 4 divisors (see below), whose sum is σ = 28081617900. Its totient is φ = 28075849824.

The previous prime is 28078733821. The next prime is 28078733897. The reversal of 28078733861 is 16833787082.

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 18390072100 + 9688661761 = 135610^2 + 98431^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28078733861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28078733821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1427366 + ... + 1446903.

It is an arithmetic number, because the mean of its divisors is an integer number (7020404475).

Almost surely, 2^28078733861 is an apocalyptic number.

It is an amenable number.

28078733861 is a deficient number, since it is larger than the sum of its proper divisors (2884039).

28078733861 is an equidigital number, since it uses as much as digits as its factorization.

28078733861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2884038.

The product of its (nonzero) digits is 2709504, while the sum is 53.

The spelling of 28078733861 in words is "twenty-eight billion, seventy-eight million, seven hundred thirty-three thousand, eight hundred sixty-one".