21317051603 has 2 divisors, whose sum is σ = 21317051604. Its totient is φ = 21317051602.

The previous prime is 21317051599. The next prime is 21317051611. The reversal of 21317051603 is 30615071312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21317051603 - 2² = 21317051599 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21317051303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10658525801 + 10658525802.

It is an arithmetic number, because the mean of its divisors is an integer number (10658525802).

Almost surely, 2^21317051603 is an apocalyptic number.

21317051603 is a deficient number, since it is larger than the sum of its proper divisors (1).

21317051603 is an equidigital number, since it uses as much as digits as its factorization.

21317051603 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3780, while the sum is 29.

The spelling of 21317051603 in words is "twenty-one billion, three hundred seventeen million, fifty-one thousand, six hundred three".