21011211121218 has 32 divisors (see below), whose sum is σ = 42339278793600. Its totient is φ = 6951012182400.

The previous prime is 21011211121211. The next prime is 21011211121231. The reversal of 21011211121218 is 81212111211012.

It is not an unprimeable number, because it can be changed into a prime (21011211121211) 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 15 ways as a sum of consecutive naturals, for example, 9576393 + ... + 11564156.

It is an arithmetic number, because the mean of its divisors is an integer number (1323102462300).

Almost surely, 2^{21011211121218} is an apocalyptic number.

21011211121218 is an abundant number, since it is smaller than the sum of its proper divisors (21328067672382).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21011211121218 is a wasteful number, since it uses less digits than its factorization.

21011211121218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21141802.

The product of its (nonzero) digits is 128, while the sum is 24.

The spelling of 21011211121218 in words is "twenty-one trillion, eleven billion, two hundred eleven million, one hundred twenty-one thousand, two hundred eighteen".