28380505861 has 2 divisors, whose sum is σ = 28380505862. Its totient is φ = 28380505860.

The previous prime is 28380505801. The next prime is 28380505871. The reversal of 28380505861 is 16850508382.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22049280100 + 6331225761 = 148490^2 + 79569^2 .

It is a cyclic number.

It is not a de Polignac number, because 28380505861 - 2⁷ = 28380505733 is a prime.

It is a super-2 number, since 2×28380505861² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28380505801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14190252930 + 14190252931.

It is an arithmetic number, because the mean of its divisors is an integer number (14190252931).

Almost surely, 2^28380505861 is an apocalyptic number.

It is an amenable number.

28380505861 is a deficient number, since it is larger than the sum of its proper divisors (1).

28380505861 is an equidigital number, since it uses as much as digits as its factorization.

28380505861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 460800, while the sum is 46.

The spelling of 28380505861 in words is "twenty-eight billion, three hundred eighty million, five hundred five thousand, eight hundred sixty-one".