21001000121010 has 96 divisors (see below), whose sum is σ = 67203200413440. Its totient is φ = 4430980243584.

The previous prime is 21001000120999. The next prime is 21001000121011. The reversal of 21001000121010 is 1012100010012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21001000120983 and 21001000121001.

It is not an unprimeable number, because it can be changed into a prime (21001000121011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1282104150 + ... + 1282120529.

It is an arithmetic number, because the mean of its divisors is an integer number (700033337640).

Almost surely, 2^{21001000121010} is an apocalyptic number.

21001000121010 is an abundant number, since it is smaller than the sum of its proper divisors (46202200292430).

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

21001000121010 is a wasteful number, since it uses less digits than its factorization.

21001000121010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2564224712 (or 2564224709 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21001000121010 its reverse (1012100010012), we get a palindrome (22013100131022).

The spelling of 21001000121010 in words is "twenty-one trillion, one billion, one hundred twenty-one thousand, ten".