21000010120 has 32 divisors (see below), whose sum is σ = 48879336600.
Its totient is φ = 8110348288.
The previous prime is 21000010103. The next prime is 21000010133. The reversal of 21000010120 is 2101000012.
It can be written as a sum of positive squares in 4 ways, for example, as 15708611556 + 5291398564 = 125334^2 + 72742^2
It is an unprimeable number.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9050569 + ... + 9052888.
Almost surely, 221000010120 is an apocalyptic number.
21000010120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.
It is an amenable number.
21000010120 is an abundant number, since it is smaller than the sum of its proper divisors (27879326480).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
21000010120 is a wasteful number, since it uses less digits than its factorization.
21000010120 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 18103497 (or 18103493 counting only the distinct ones).
The product of its (nonzero) digits is 4, while the sum is 7.
Adding to 21000010120 its reverse (2101000012), we get a palindrome (23101010132).
The spelling of 21000010120 in words is "twenty-one billion, ten thousand, one hundred twenty".