28810356581 has 2 divisors, whose sum is σ = 28810356582. Its totient is φ = 28810356580.

The previous prime is 28810356551. The next prime is 28810356643. The reversal of 28810356581 is 18565301882.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16958550625 + 11851805956 = 130225^2 + 108866^2 .

It is a cyclic number.

It is not a de Polignac number, because 28810356581 - 2¹⁴ = 28810340197 is a prime.

It is a super-2 number, since 2×28810356581² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28810356521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14405178290 + 14405178291.

It is an arithmetic number, because the mean of its divisors is an integer number (14405178291).

Almost surely, 2^28810356581 is an apocalyptic number.

It is an amenable number.

28810356581 is a deficient number, since it is larger than the sum of its proper divisors (1).

28810356581 is an equidigital number, since it uses as much as digits as its factorization.

28810356581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 460800, while the sum is 47.

The spelling of 28810356581 in words is "twenty-eight billion, eight hundred ten million, three hundred fifty-six thousand, five hundred eighty-one".