21000120010 has 32 divisors (see below), whose sum is σ = 38158901712. Its totient is φ = 8320435200.

The previous prime is 21000119999. The next prime is 21000120013. The reversal of 21000120010 is 1002100012.

It can be written as a sum of positive squares in 8 ways, for example, as 9631655881 + 11368464129 = 98141^2 + 106623^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21000119975 and 21000120002.

It is not an unprimeable number, because it can be changed into a prime (21000120013) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2116060 + ... + 2125960.

Almost surely, 2^21000120010 is an apocalyptic number.

21000120010 is a deficient number, since it is larger than the sum of its proper divisors (17158781702).

21000120010 is a wasteful number, since it uses less digits than its factorization.

21000120010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11898.

The product of its (nonzero) digits is 4, while the sum is 7.

Adding to 21000120010 its reverse (1002100012), we get a palindrome (22002220022).

The spelling of 21000120010 in words is "twenty-one billion, one hundred twenty thousand, ten".