21512501109611 has 2 divisors, whose sum is σ = 21512501109612. Its totient is φ = 21512501109610.

The previous prime is 21512501109553. The next prime is 21512501109613. The reversal of 21512501109611 is 11690110521512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21512501109611 - 2¹⁰ = 21512501108587 is a prime.

Together with 21512501109613, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21512501109613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10756250554805 + 10756250554806.

It is an arithmetic number, because the mean of its divisors is an integer number (10756250554806).

Almost surely, 2^{21512501109611} is an apocalyptic number.

21512501109611 is a deficient number, since it is larger than the sum of its proper divisors (1).

21512501109611 is an equidigital number, since it uses as much as digits as its factorization.

21512501109611 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 35.

The spelling of 21512501109611 in words is "twenty-one trillion, five hundred twelve billion, five hundred one million, one hundred nine thousand, six hundred eleven".