28040420861 has 2 divisors, whose sum is σ = 28040420862. Its totient is φ = 28040420860.

The previous prime is 28040420833. The next prime is 28040420879. The reversal of 28040420861 is 16802404082.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20257828900 + 7782591961 = 142330^2 + 88219^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28040420861 is a prime.

It is a super-3 number, since 3×28040420861³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28040020861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14020210430 + 14020210431.

It is an arithmetic number, because the mean of its divisors is an integer number (14020210431).

Almost surely, 2^28040420861 is an apocalyptic number.

It is an amenable number.

28040420861 is a deficient number, since it is larger than the sum of its proper divisors (1).

28040420861 is an equidigital number, since it uses as much as digits as its factorization.

28040420861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24576, while the sum is 35.

The spelling of 28040420861 in words is "twenty-eight billion, forty million, four hundred twenty thousand, eight hundred sixty-one".