21221011221218 has 16 divisors (see below), whose sum is σ = 31879860629760. Its totient is φ = 10594395942816.

The previous prime is 21221011221217. The next prime is 21221011221283. The reversal of 21221011221218 is 81212211012212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21221011221217) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7399598 + ... + 9858806.

It is an arithmetic number, because the mean of its divisors is an integer number (1992491289360).

Almost surely, 2^{21221011221218} is an apocalyptic number.

21221011221218 is a deficient number, since it is larger than the sum of its proper divisors (10658849408542).

21221011221218 is a wasteful number, since it uses less digits than its factorization.

21221011221218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2465761.

The product of its (nonzero) digits is 512, while the sum is 26.

The spelling of 21221011221218 in words is "twenty-one trillion, two hundred twenty-one billion, eleven million, two hundred twenty-one thousand, two hundred eighteen".