28178739401 has 4 divisors (see below), whose sum is σ = 29150420100. Its totient is φ = 27207058704.

The previous prime is 28178739359. The next prime is 28178739443. The reversal of 28178739401 is 10493787182.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10493787182 = 2 ⋅5246893591.

It is an interprime number because it is at equal distance from previous prime (28178739359) and next prime (28178739443).

It can be written as a sum of positive squares in 2 ways, for example, as 22326336400 + 5852403001 = 149420^2 + 76501^2 .

It is a cyclic number.

It is not a de Polignac number, because 28178739401 - 2¹⁴ = 28178723017 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 28178739401.

It is not an unprimeable number, because it can be changed into a prime (28178739481) 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, 485840306 + ... + 485840363.

It is an arithmetic number, because the mean of its divisors is an integer number (7287605025).

Almost surely, 2^28178739401 is an apocalyptic number.

It is an amenable number.

28178739401 is a deficient number, since it is larger than the sum of its proper divisors (971680699).

28178739401 is an equidigital number, since it uses as much as digits as its factorization.

28178739401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 971680698.

The product of its (nonzero) digits is 677376, while the sum is 50.

The spelling of 28178739401 in words is "twenty-eight billion, one hundred seventy-eight million, seven hundred thirty-nine thousand, four hundred one".