21301013509 has 2 divisors, whose sum is σ = 21301013510. Its totient is φ = 21301013508.

The previous prime is 21301013473. The next prime is 21301013519. The reversal of 21301013509 is 90531010312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19141552609 + 2159460900 = 138353^2 + 46470^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21301013509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21301013519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650506754 + 10650506755.

It is an arithmetic number, because the mean of its divisors is an integer number (10650506755).

Almost surely, 2^21301013509 is an apocalyptic number.

It is an amenable number.

21301013509 is a deficient number, since it is larger than the sum of its proper divisors (1).

21301013509 is an equidigital number, since it uses as much as digits as its factorization.

21301013509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 810, while the sum is 25.

The spelling of 21301013509 in words is "twenty-one billion, three hundred one million, thirteen thousand, five hundred nine".