287768811685921 has 2 divisors, whose sum is σ = 287768811685922. Its totient is φ = 287768811685920.

The previous prime is 287768811685909. The next prime is 287768811685931. The reversal of 287768811685921 is 129586118867782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 162813414746896 + 124955396939025 = 12759836^2 + 11178345^2 .

It is a cyclic number.

It is not a de Polignac number, because 287768811685921 - 2²⁵ = 287768778131489 is a prime.

It is not a weakly prime, because it can be changed into another prime (287768811685931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 143884405842960 + 143884405842961.

It is an arithmetic number, because the mean of its divisors is an integer number (143884405842961).

Almost surely, 2^{287768811685921} is an apocalyptic number.

It is an amenable number.

287768811685921 is a deficient number, since it is larger than the sum of its proper divisors (1).

287768811685921 is an equidigital number, since it uses as much as digits as its factorization.

287768811685921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1300561920, while the sum is 79.

The spelling of 287768811685921 in words is "two hundred eighty-seven trillion, seven hundred sixty-eight billion, eight hundred eleven million, six hundred eighty-five thousand, nine hundred twenty-one".