21210020021005 has 8 divisors (see below), whose sum is σ = 25452375672600. Its totient is φ = 16967781585216.

The previous prime is 21210020020907. The next prime is 21210020021023. The reversal of 21210020021005 is 50012002001212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 284646791529 + 20925373229476 = 533523^2 + 4574426^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21210020021005 - 2³⁹ = 20660264207117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21210020021005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28905370 + ... + 29630059.

It is an arithmetic number, because the mean of its divisors is an integer number (3181546959075).

Almost surely, 2^{21210020021005} is an apocalyptic number.

It is an amenable number.

21210020021005 is a deficient number, since it is larger than the sum of its proper divisors (4242355651595).

21210020021005 is an equidigital number, since it uses as much as digits as its factorization.

21210020021005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58607903.

The product of its (nonzero) digits is 80, while the sum is 16.

Adding to 21210020021005 its reverse (50012002001212), we get a palindrome (71222022022217).

The spelling of 21210020021005 in words is "twenty-one trillion, two hundred ten billion, twenty million, twenty-one thousand, five".