1211000000 has 196 divisors, whose sum is σ = 3452768304. Its totient is φ = 412800000.

The previous prime is 1210999987. The next prime is 1211000023. The reversal of 1211000000 is 1121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (5).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 6999914 + ... + 7000086.

Almost surely, 2^1211000000 is an apocalyptic number.

1211000000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1211000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1726384152).

1211000000 is an abundant number, since it is smaller than the sum of its proper divisors (2241768304).

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

1211000000 is an frugal number, since it uses more digits than its factorization.

1211000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222 (or 187 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 5.

The square root of 1211000000 is about 34799.4252826106. The cubic root of 1211000000 is about 1065.8957102700.

Adding to 1211000000 its reverse (1121), we get a palindrome (1211001121).

The spelling of 1211000000 in words is "one billion, two hundred eleven million", and thus it is an aban number.