28749647557 has 2 divisors, whose sum is σ = 28749647558. Its totient is φ = 28749647556.

The previous prime is 28749647527. The next prime is 28749647573. The reversal of 28749647557 is 75574694782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20990504161 + 7759143396 = 144881^2 + 88086^2 .

It is a cyclic number.

It is not a de Polignac number, because 28749647557 - 2³¹ = 26602163909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28749647527) 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 as a sum of consecutive naturals, namely, 14374823778 + 14374823779.

It is an arithmetic number, because the mean of its divisors is an integer number (14374823779).

Almost surely, 2^28749647557 is an apocalyptic number.

It is an amenable number.

28749647557 is a deficient number, since it is larger than the sum of its proper divisors (1).

28749647557 is an equidigital number, since it uses as much as digits as its factorization.

28749647557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 118540800, while the sum is 64.

The spelling of 28749647557 in words is "twenty-eight billion, seven hundred forty-nine million, six hundred forty-seven thousand, five hundred fifty-seven".