28881851909 has 2 divisors, whose sum is σ = 28881851910. Its totient is φ = 28881851908.

The previous prime is 28881851899. The next prime is 28881851951. The reversal of 28881851909 is 90915818882.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28867029409 + 14822500 = 169903^2 + 3850^2 .

It is a cyclic number.

It is not a de Polignac number, because 28881851909 - 2²⁰ = 28880803333 is a prime.

It is a super-2 number, since 2×28881851909² (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 (28881850909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14440925954 + 14440925955.

It is an arithmetic number, because the mean of its divisors is an integer number (14440925955).

Almost surely, 2^28881851909 is an apocalyptic number.

It is an amenable number.

28881851909 is a deficient number, since it is larger than the sum of its proper divisors (1).

28881851909 is an equidigital number, since it uses as much as digits as its factorization.

28881851909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3317760, while the sum is 59.

The spelling of 28881851909 in words is "twenty-eight billion, eight hundred eighty-one million, eight hundred fifty-one thousand, nine hundred nine".