8781855654421 has 2 divisors, whose sum is σ = 8781855654422. Its totient is φ = 8781855654420.

The previous prime is 8781855654389. The next prime is 8781855654433. The reversal of 8781855654421 is 1244565581878.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4695191251921 + 4086664402500 = 2166839^2 + 2021550^2 .

It is a cyclic number.

It is not a de Polignac number, because 8781855654421 - 2⁵ = 8781855654389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8781855654461) 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, 4390927827210 + 4390927827211.

It is an arithmetic number, because the mean of its divisors is an integer number (4390927827211).

Almost surely, 2^{8781855654421} is an apocalyptic number.

It is an amenable number.

8781855654421 is a deficient number, since it is larger than the sum of its proper divisors (1).

8781855654421 is an equidigital number, since it uses as much as digits as its factorization.

8781855654421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 86016000, while the sum is 64.

The spelling of 8781855654421 in words is "eight trillion, seven hundred eighty-one billion, eight hundred fifty-five million, six hundred fifty-four thousand, four hundred twenty-one".