1210661100 has 144 divisors (see below), whose sum is σ = 4245978240. Its totient is φ = 293486400.

The previous prime is 1210661071. The next prime is 1210661113. The reversal of 1210661100 is 11660121.

1210661100 is a `hidden beast` number, since 1 + 2 + 1 + 0 + 661 + 1 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 9319 + ... + 50081.

It is an arithmetic number, because the mean of its divisors is an integer number (29485960).

Almost surely, 2^1210661100 is an apocalyptic number.

1210661100 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 1210661100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2122989120).

1210661100 is an abundant number, since it is smaller than the sum of its proper divisors (3035317140).

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

1210661100 is a wasteful number, since it uses less digits than its factorization.

1210661100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40797 (or 40784 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 1210661100 is about 34794.5556086006. Note that the first 3 decimals coincide. The cubic root of 1210661100 is about 1065.7962702043.

The spelling of 1210661100 in words is "one billion, two hundred ten million, six hundred sixty-one thousand, one hundred".