21000120218 has 48 divisors (see below), whose sum is σ = 40037934528. Its totient is φ = 8168832000.

The previous prime is 21000120217. The next prime is 21000120221. The reversal of 21000120218 is 81202100012.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21000120196 and 21000120205.

It is not an unprimeable number, because it can be changed into a prime (21000120217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 675803 + ... + 706193.

It is an arithmetic number, because the mean of its divisors is an integer number (834123636).

Almost surely, 2^21000120218 is an apocalyptic number.

21000120218 is a deficient number, since it is larger than the sum of its proper divisors (19037814310).

21000120218 is a wasteful number, since it uses less digits than its factorization.

21000120218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31059 (or 31052 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

The spelling of 21000120218 in words is "twenty-one billion, one hundred twenty thousand, two hundred eighteen".