121221211110 has 64 divisors (see below), whose sum is σ = 292211877888. Its totient is φ = 32183548544.

The previous prime is 121221211091. The next prime is 121221211121. The reversal of 121221211110 is 11112122121.

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 121221211110.

It is a congruent number.

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, 9689119 + ... + 9701621.

It is an arithmetic number, because the mean of its divisors is an integer number (4565810592).

Almost surely, 2^121221211110 is an apocalyptic number.

121221211110 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

121221211110 is an abundant number, since it is smaller than the sum of its proper divisors (170990666778).

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

121221211110 is a wasteful number, since it uses less digits than its factorization.

121221211110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13909.

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

Adding to 121221211110 its reverse (11112122121), we get a palindrome (132333333231).

The spelling of 121221211110 in words is "one hundred twenty-one billion, two hundred twenty-one million, two hundred eleven thousand, one hundred ten".