21011212121210 has 16 divisors (see below), whose sum is σ = 37824617316096. Its totient is φ = 8403499182288.

The previous prime is 21011212121209. The next prime is 21011212121293. The reversal of 21011212121210 is 1212121211012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 123118742 + ... + 123289281.

It is an arithmetic number, because the mean of its divisors is an integer number (2364038582256).

Almost surely, 2^{21011212121210} is an apocalyptic number.

21011212121210 is a deficient number, since it is larger than the sum of its proper divisors (16813405194886).

21011212121210 is a wasteful number, since it uses less digits than its factorization.

21011212121210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246416557.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21011212121210 its reverse (1212121211012), we get a palindrome (22223333332222).

The spelling of 21011212121210 in words is "twenty-one trillion, eleven billion, two hundred twelve million, one hundred twenty-one thousand, two hundred ten".