1221210110 has 16 divisors (see below), whose sum is σ = 2199609216. Its totient is φ = 488166048.

The previous prime is 1221210043. The next prime is 1221210119. The reversal of 1221210110 is 110121221.

It is a junction number, because it is equal to n+sod(n) for n = 1221210091 and 1221210100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221210119) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23297 + ... + 54636.

It is an arithmetic number, because the mean of its divisors is an integer number (137475576).

Almost surely, 2^1221210110 is an apocalyptic number.

1221210110 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221210110 is a deficient number, since it is larger than the sum of its proper divisors (978399106).

1221210110 is a wasteful number, since it uses less digits than its factorization.

1221210110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79507.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 1221210110 is about 34945.8167739717. The cubic root of 1221210110 is about 1068.8829026156.

Adding to 1221210110 its reverse (110121221), we get a palindrome (1331331331).

Subtracting from 1221210110 its reverse (110121221), we obtain a square (1111088889 = 33333²).

It can be divided in two parts, 12212 and 10110, that added together give a palindrome (22322).

The spelling of 1221210110 in words is "one billion, two hundred twenty-one million, two hundred ten thousand, one hundred ten".