21100508503 has 2 divisors, whose sum is σ = 21100508504. Its totient is φ = 21100508502.

The previous prime is 21100508467. The next prime is 21100508549. The reversal of 21100508503 is 30580500112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21100508503 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21100508563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550254251 + 10550254252.

It is an arithmetic number, because the mean of its divisors is an integer number (10550254252).

Almost surely, 2^21100508503 is an apocalyptic number.

21100508503 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100508503 is an equidigital number, since it uses as much as digits as its factorization.

21100508503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1200, while the sum is 25.

The spelling of 21100508503 in words is "twenty-one billion, one hundred million, five hundred eight thousand, five hundred three".