21200102012521 has 2 divisors, whose sum is σ = 21200102012522. Its totient is φ = 21200102012520.

The previous prime is 21200102012519. The next prime is 21200102012567. The reversal of 21200102012521 is 12521020100212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16952941586025 + 4247160426496 = 4117395^2 + 2060864^2 .

It is a cyclic number.

It is not a de Polignac number, because 21200102012521 - 2¹ = 21200102012519 is a prime.

Together with 21200102012519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21200102012591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600051006260 + 10600051006261.

It is an arithmetic number, because the mean of its divisors is an integer number (10600051006261).

Almost surely, 2^{21200102012521} is an apocalyptic number.

It is an amenable number.

21200102012521 is a deficient number, since it is larger than the sum of its proper divisors (1).

21200102012521 is an equidigital number, since it uses as much as digits as its factorization.

21200102012521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 160, while the sum is 19.

Adding to 21200102012521 its reverse (12521020100212), we get a palindrome (33721122112733).

The spelling of 21200102012521 in words is "twenty-one trillion, two hundred billion, one hundred two million, twelve thousand, five hundred twenty-one".