1221111111210 has 32 divisors (see below), whose sum is σ = 2931444509760. Its totient is φ = 325543202688.

The previous prime is 1221111111173. The next prime is 1221111111263. The reversal of 1221111111210 is 121111111221.

It is a super-2 number, since 2×1221111111210² (a number of 25 digits) contains 22 as substring.

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

It is a self number, because there is not a number n which added to its sum of digits gives 1221111111210.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5286732 + ... + 5512871.

It is an arithmetic number, because the mean of its divisors is an integer number (91607640930).

Almost surely, 2^{1221111111210} is an apocalyptic number.

1221111111210 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221111111210 is an abundant number, since it is smaller than the sum of its proper divisors (1710333398550).

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

1221111111210 is a wasteful number, since it uses less digits than its factorization.

1221111111210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10803382.

The product of its (nonzero) digits is 8, while the sum is 15.

Adding to 1221111111210 its reverse (121111111221), we get a palindrome (1342222222431).

It can be divided in two parts, 122111 and 1111210, that added together give a palindrome (1233321).

The spelling of 1221111111210 in words is "one trillion, two hundred twenty-one billion, one hundred eleven million, one hundred eleven thousand, two hundred ten".