21520003018009 has 2 divisors, whose sum is σ = 21520003018010. Its totient is φ = 21520003018008.

The previous prime is 21520003018001. The next prime is 21520003018021. The reversal of 21520003018009 is 90081030002512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16850795120784 + 4669207897225 = 4104972^2 + 2160835^2 .

It is a cyclic number.

It is not a de Polignac number, because 21520003018009 - 2³ = 21520003018001 is a prime.

It is a super-2 number, since 2×21520003018009² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21520003018001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10760001509004 + 10760001509005.

It is an arithmetic number, because the mean of its divisors is an integer number (10760001509005).

Almost surely, 2^{21520003018009} is an apocalyptic number.

It is an amenable number.

21520003018009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21520003018009 is an equidigital number, since it uses as much as digits as its factorization.

21520003018009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 31.

The spelling of 21520003018009 in words is "twenty-one trillion, five hundred twenty billion, three million, eighteen thousand, nine".