28814745581 has 2 divisors, whose sum is σ = 28814745582. Its totient is φ = 28814745580.

The previous prime is 28814745541. The next prime is 28814745607. The reversal of 28814745581 is 18554741882.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16619077225 + 12195668356 = 128915^2 + 110434^2 .

It is a cyclic number.

It is not a de Polignac number, because 28814745581 - 2⁶ = 28814745517 is a prime.

It is a super-2 number, since 2×28814745581² (a number of 22 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28814745521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14407372790 + 14407372791.

It is an arithmetic number, because the mean of its divisors is an integer number (14407372791).

Almost surely, 2^28814745581 is an apocalyptic number.

It is an amenable number.

28814745581 is a deficient number, since it is larger than the sum of its proper divisors (1).

28814745581 is an equidigital number, since it uses as much as digits as its factorization.

28814745581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2867200, while the sum is 53.

The spelling of 28814745581 in words is "twenty-eight billion, eight hundred fourteen million, seven hundred forty-five thousand, five hundred eighty-one".