21854388649 has 8 divisors (see below), whose sum is σ = 22844933120. Its totient is φ = 20881692000.

The previous prime is 21854388637. The next prime is 21854388679. The reversal of 21854388649 is 94688345812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21854388649 - 2¹⁵ = 21854355881 is a prime.

It is a super-2 number, since 2×21854388649² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21854388593 and 21854388602.

It is not an unprimeable number, because it can be changed into a prime (21854388679) 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 7 ways as a sum of consecutive naturals, for example, 4459452 + ... + 4464349.

It is an arithmetic number, because the mean of its divisors is an integer number (2855616640).

Almost surely, 2^21854388649 is an apocalyptic number.

It is an amenable number.

21854388649 is a deficient number, since it is larger than the sum of its proper divisors (990544471).

21854388649 is an equidigital number, since it uses as much as digits as its factorization.

21854388649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8923911.

The product of its digits is 13271040, while the sum is 58.

The spelling of 21854388649 in words is "twenty-one billion, eight hundred fifty-four million, three hundred eighty-eight thousand, six hundred forty-nine".