21310202909 has 2 divisors, whose sum is σ = 21310202910. Its totient is φ = 21310202908.

The previous prime is 21310202897. The next prime is 21310203049. The reversal of 21310202909 is 90920201312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15476604025 + 5833598884 = 124405^2 + 76378^2 .

It is a cyclic number.

It is not a de Polignac number, because 21310202909 - 2⁸ = 21310202653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21310202509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655101454 + 10655101455.

It is an arithmetic number, because the mean of its divisors is an integer number (10655101455).

Almost surely, 2^21310202909 is an apocalyptic number.

It is an amenable number.

21310202909 is a deficient number, since it is larger than the sum of its proper divisors (1).

21310202909 is an equidigital number, since it uses as much as digits as its factorization.

21310202909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 29.

The spelling of 21310202909 in words is "twenty-one billion, three hundred ten million, two hundred two thousand, nine hundred nine".