21510853213 has 2 divisors, whose sum is σ = 21510853214. Its totient is φ = 21510853212.

The previous prime is 21510853183. The next prime is 21510853241. The reversal of 21510853213 is 31235801512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10843681689 + 10667171524 = 104133^2 + 103282^2 .

It is a cyclic number.

It is not a de Polignac number, because 21510853213 - 2¹³ = 21510845021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21510853513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10755426606 + 10755426607.

It is an arithmetic number, because the mean of its divisors is an integer number (10755426607).

Almost surely, 2^21510853213 is an apocalyptic number.

It is an amenable number.

21510853213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21510853213 is an equidigital number, since it uses as much as digits as its factorization.

21510853213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7200, while the sum is 31.

The spelling of 21510853213 in words is "twenty-one billion, five hundred ten million, eight hundred fifty-three thousand, two hundred thirteen".