1220121100 has 72 divisors (see below), whose sum is σ = 3040430400. Its totient is φ = 420321600.

The previous prime is 1220121083. The next prime is 1220121113. The reversal of 1220121100 is 11210221.

It is a super-3 number, since 3×1220121100³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8290 + ... + 50089.

It is an arithmetic number, because the mean of its divisors is an integer number (42228200).

Almost surely, 2^1220121100 is an apocalyptic number.

1220121100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1220121100 is an abundant number, since it is smaller than the sum of its proper divisors (1820309300).

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

1220121100 is a wasteful number, since it uses less digits than its factorization.

1220121100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58423 (or 58416 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 1220121100 is about 34930.2318915864. The cubic root of 1220121100 is about 1068.5650838836.

Adding to 1220121100 its reverse (11210221), we get a palindrome (1231331321).

It can be divided in two parts, 1220121 and 100, that added together give a palindrome (1220221).

The spelling of 1220121100 in words is "one billion, two hundred twenty million, one hundred twenty-one thousand, one hundred".