1221220021110 has 32 divisors (see below), whose sum is σ = 3103335584352. Its totient is φ = 306502279680.

The previous prime is 1221220021097. The next prime is 1221220021117. The reversal of 1221220021110 is 111200221221.

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 1221220021110.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221220021117) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1197274021 + ... + 1197275040.

It is an arithmetic number, because the mean of its divisors is an integer number (96979237011).

Almost surely, 2^{1221220021110} is an apocalyptic number.

1221220021110 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221220021110 is an abundant number, since it is smaller than the sum of its proper divisors (1882115563242).

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

1221220021110 is a wasteful number, since it uses less digits than its factorization.

1221220021110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2394549088.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 1221220021110 its reverse (111200221221), we get a palindrome (1332420242331).

The spelling of 1221220021110 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, twenty-one thousand, one hundred ten".