21854555406787 has 4 divisors (see below), whose sum is σ = 21854588169456. Its totient is φ = 21854522644120.

The previous prime is 21854555406721. The next prime is 21854555406829. The reversal of 21854555406787 is 78760455545812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21854555406787 - 2¹⁵ = 21854555374019 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21854555406487) 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 in 3 ways as a sum of consecutive naturals, for example, 15359503 + ... + 16721944.

It is an arithmetic number, because the mean of its divisors is an integer number (5463647042364).

Almost surely, 2^{21854555406787} is an apocalyptic number.

21854555406787 is a deficient number, since it is larger than the sum of its proper divisors (32762669).

21854555406787 is an equidigital number, since it uses as much as digits as its factorization.

21854555406787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32762668.

The product of its (nonzero) digits is 376320000, while the sum is 67.

The spelling of 21854555406787 in words is "twenty-one trillion, eight hundred fifty-four billion, five hundred fifty-five million, four hundred six thousand, seven hundred eighty-seven".