1009100900 has 72 divisors (see below), whose sum is σ = 2238164040. Its totient is φ = 394813440.

The previous prime is 1009100893. The next prime is 1009100903. The reversal of 1009100900 is 90019001.

It can be written as a sum of positive squares in 12 ways, for example, as 280964644 + 728136256 = 16762^2 + 26984^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (1009100903) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 999596 + ... + 1000604.

Almost surely, 2^1009100900 is an apocalyptic number.

1009100900 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 1009100900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1119082020).

1009100900 is an abundant number, since it is smaller than the sum of its proper divisors (1229063140).

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

1009100900 is a wasteful number, since it uses less digits than its factorization.

1009100900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1233 (or 1226 counting only the distinct ones).

The product of its (nonzero) digits is 81, while the sum is 20.

The square root of 1009100900 is about 31766.3485468506. The cubic root of 1009100900 is about 1003.0244766522.

Adding to 1009100900 its reverse (90019001), we get a palindrome (1099119901).

It can be divided in two parts, 1009 and 100900, that multiplied together give a square (101808100 = 10090²).

The spelling of 1009100900 in words is "one billion, nine million, one hundred thousand, nine hundred".