21647302913 has 2 divisors, whose sum is σ = 21647302914. Its totient is φ = 21647302912.

The previous prime is 21647302841. The next prime is 21647302921. The reversal of 21647302913 is 31920374612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21622820209 + 24482704 = 147047^2 + 4948^2 .

It is a cyclic number.

It is not a de Polignac number, because 21647302913 - 2¹⁰ = 21647301889 is a prime.

It is not a weakly prime, because it can be changed into another prime (21647302973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10823651456 + 10823651457.

It is an arithmetic number, because the mean of its divisors is an integer number (10823651457).

Almost surely, 2^21647302913 is an apocalyptic number.

It is an amenable number.

21647302913 is a deficient number, since it is larger than the sum of its proper divisors (1).

21647302913 is an equidigital number, since it uses as much as digits as its factorization.

21647302913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 38.

The spelling of 21647302913 in words is "twenty-one billion, six hundred forty-seven million, three hundred two thousand, nine hundred thirteen".