21210012011021 has 8 divisors (see below), whose sum is σ = 21497340721944. Its totient is φ = 20924199547200.

The previous prime is 21210012010939. The next prime is 21210012011047. The reversal of 21210012011021 is 12011021001212.

It can be written as a sum of positive squares in 4 ways, for example, as 279432760996 + 20930579250025 = 528614^2 + 4574995^2 .

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-21210012011021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21210012010987 and 21210012011005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210012016021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 379033610 + ... + 379089563.

It is an arithmetic number, because the mean of its divisors is an integer number (2687167590243).

Almost surely, 2^{21210012011021} is an apocalyptic number.

It is an amenable number.

21210012011021 is a deficient number, since it is larger than the sum of its proper divisors (287328710923).

21210012011021 is a wasteful number, since it uses less digits than its factorization.

21210012011021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 758123551.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21210012011021 its reverse (12011021001212), we get a palindrome (33221033012233).

The spelling of 21210012011021 in words is "twenty-one trillion, two hundred ten billion, twelve million, eleven thousand, twenty-one".