21507527006309 has 2 divisors, whose sum is σ = 21507527006310. Its totient is φ = 21507527006308.

The previous prime is 21507527006233. The next prime is 21507527006311. The reversal of 21507527006309 is 90360072570512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18777679555684 + 2729847450625 = 4333322^2 + 1652225^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21507527006309 is a prime.

It is a super-2 number, since 2×21507527006309² (a number of 27 digits) contains 22 as substring.

Together with 21507527006311, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21507527006909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10753763503154 + 10753763503155.

It is an arithmetic number, because the mean of its divisors is an integer number (10753763503155).

Almost surely, 2^{21507527006309} is an apocalyptic number.

It is an amenable number.

21507527006309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21507527006309 is an equidigital number, since it uses as much as digits as its factorization.

21507527006309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 793800, while the sum is 47.

The spelling of 21507527006309 in words is "twenty-one trillion, five hundred seven billion, five hundred twenty-seven million, six thousand, three hundred nine".