21200012120021 has 8 divisors (see below), whose sum is σ = 24231446879040. Its totient is φ = 18169292760768.

The previous prime is 21200012120011. The next prime is 21200012120059. The reversal of 21200012120021 is 12002121000212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21200012120021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21200012119978 and 21200012120005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200012120011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 178786436 + ... + 178904973.

It is an arithmetic number, because the mean of its divisors is an integer number (3028930859880).

Almost surely, 2^{21200012120021} is an apocalyptic number.

It is an amenable number.

21200012120021 is a deficient number, since it is larger than the sum of its proper divisors (3031434759019).

21200012120021 is an equidigital number, since it uses as much as digits as its factorization.

21200012120021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 357699883.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21200012120021 its reverse (12002121000212), we get a palindrome (33202133120233).

The spelling of 21200012120021 in words is "twenty-one trillion, two hundred billion, twelve million, one hundred twenty thousand, twenty-one".