28780528385491 has 2 divisors, whose sum is σ = 28780528385492. Its totient is φ = 28780528385490.

The previous prime is 28780528385437. The next prime is 28780528385551. The reversal of 28780528385491 is 19458382508782.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28780528385491 - 2⁷ = 28780528385363 is a prime.

It is a super-4 number, since 4×28780528385491⁴ (a number of 55 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 28780528385491.

It is not a weakly prime, because it can be changed into another prime (28780528485491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14390264192745 + 14390264192746.

It is an arithmetic number, because the mean of its divisors is an integer number (14390264192746).

Almost surely, 2^{28780528385491} is an apocalyptic number.

28780528385491 is a deficient number, since it is larger than the sum of its proper divisors (1).

28780528385491 is an equidigital number, since it uses as much as digits as its factorization.

28780528385491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 309657600, while the sum is 70.

The spelling of 28780528385491 in words is "twenty-eight trillion, seven hundred eighty billion, five hundred twenty-eight million, three hundred eighty-five thousand, four hundred ninety-one".