21202948817 has 2 divisors, whose sum is σ = 21202948818. Its totient is φ = 21202948816.

The previous prime is 21202948763. The next prime is 21202948829. The reversal of 21202948817 is 71884920212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20874759361 + 328189456 = 144481^2 + 18116^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202948817 - 2¹⁶ = 21202883281 is a prime.

It is a super-4 number, since 4×21202948817⁴ (a number of 42 digits) contains 4444 as substring.

It is not a weakly prime, because it can be changed into another prime (21202948517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601474408 + 10601474409.

It is an arithmetic number, because the mean of its divisors is an integer number (10601474409).

Almost surely, 2^21202948817 is an apocalyptic number.

It is an amenable number.

21202948817 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202948817 is an equidigital number, since it uses as much as digits as its factorization.

21202948817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 129024, while the sum is 44.

The spelling of 21202948817 in words is "twenty-one billion, two hundred two million, nine hundred forty-eight thousand, eight hundred seventeen".