1221212110 has 16 divisors (see below), whose sum is σ = 2199507696. Its totient is φ = 488190208.

The previous prime is 1221212089. The next prime is 1221212143. The reversal of 1221212110 is 112121221.

It is a super-2 number, since 2×1221212110² = 2982718035221304200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19012 + ... + 52951.

It is an arithmetic number, because the mean of its divisors is an integer number (137469231).

Almost surely, 2^1221212110 is an apocalyptic number.

1221212110 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221212110 is a deficient number, since it is larger than the sum of its proper divisors (978295586).

1221212110 is a wasteful number, since it uses less digits than its factorization.

1221212110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73667.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 1221212110 is about 34945.8453896883. The cubic root of 1221212110 is about 1068.8834861256.

Adding to 1221212110 its reverse (112121221), we get a palindrome (1333333331).

The spelling of 1221212110 in words is "one billion, two hundred twenty-one million, two hundred twelve thousand, one hundred ten".