1211022100 has 18 divisors (see below), whose sum is σ = 2627918174. Its totient is φ = 484408800.

The previous prime is 1211022097. The next prime is 1211022157. The reversal of 1211022100 is 12201121.

It can be written as a sum of positive squares in 3 ways, for example, as 374887044 + 836135056 = 19362^2 + 28916^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6055011 + ... + 6055210.

Almost surely, 2^1211022100 is an apocalyptic number.

1211022100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211022100 is an abundant number, since it is smaller than the sum of its proper divisors (1416896074).

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

1211022100 is a wasteful number, since it uses less digits than its factorization.

1211022100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12110235 (or 12110228 counting only the distinct ones).

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

The square root of 1211022100 is about 34799.7428151416. The cubic root of 1211022100 is about 1065.9021942094.

Adding to 1211022100 its reverse (12201121), we get a palindrome (1223223221).

The spelling of 1211022100 in words is "one billion, two hundred eleven million, twenty-two thousand, one hundred".