28507987789 has 2 divisors, whose sum is σ = 28507987790. Its totient is φ = 28507987788.

The previous prime is 28507987763. The next prime is 28507987799. The reversal of 28507987789 is 98778970582.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24051357225 + 4456630564 = 155085^2 + 66758^2 .

It is a cyclic number.

It is not a de Polignac number, because 28507987789 - 2³¹ = 26360504141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28507987709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14253993894 + 14253993895.

It is an arithmetic number, because the mean of its divisors is an integer number (14253993895).

Almost surely, 2^28507987789 is an apocalyptic number.

It is an amenable number.

28507987789 is a deficient number, since it is larger than the sum of its proper divisors (1).

28507987789 is an equidigital number, since it uses as much as digits as its factorization.

28507987789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 142248960, while the sum is 70.

The spelling of 28507987789 in words is "twenty-eight billion, five hundred seven million, nine hundred eighty-seven thousand, seven hundred eighty-nine".