111212121210 has 64 divisors (see below), whose sum is σ = 269450184960. Its totient is φ = 29374410240.

The previous prime is 111212121187. The next prime is 111212121227. The reversal of 111212121210 is 12121212111.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 111212121210.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18907470 + ... + 18913350.

It is an arithmetic number, because the mean of its divisors is an integer number (4210159140).

Almost surely, 2^111212121210 is an apocalyptic number.

111212121210 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

111212121210 is an abundant number, since it is smaller than the sum of its proper divisors (158238063750).

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

111212121210 is a wasteful number, since it uses less digits than its factorization.

111212121210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11783.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 111212121210 its reverse (12121212111), we get a palindrome (123333333321).

Subtracting from 111212121210 its reverse (12121212111), we obtain a palindrome (99090909099).

It can be divided in two parts, 1 and 11212121210, that added together give a palindrome (11212121211).

The spelling of 111212121210 in words is "one hundred eleven billion, two hundred twelve million, one hundred twenty-one thousand, two hundred ten".