21103185899 has 2 divisors, whose sum is σ = 21103185900. Its totient is φ = 21103185898.

The previous prime is 21103185881. The next prime is 21103185919. The reversal of 21103185899 is 99858130112.

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-21103185899 is a prime.

It is not a weakly prime, because it can be changed into another prime (21103185839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551592949 + 10551592950.

It is an arithmetic number, because the mean of its divisors is an integer number (10551592950).

Almost surely, 2^21103185899 is an apocalyptic number.

21103185899 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103185899 is an equidigital number, since it uses as much as digits as its factorization.

21103185899 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 155520, while the sum is 47.

The spelling of 21103185899 in words is "twenty-one billion, one hundred three million, one hundred eighty-five thousand, eight hundred ninety-nine".