21317703497 has 2 divisors, whose sum is σ = 21317703498. Its totient is φ = 21317703496.

The previous prime is 21317703487. The next prime is 21317703577. The reversal of 21317703497 is 79430771312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16994772496 + 4322931001 = 130364^2 + 65749^2 .

It is a cyclic number.

It is not a de Polignac number, because 21317703497 - 2¹⁰ = 21317702473 is a prime.

It is a super-4 number, since 4×21317703497⁴ (a number of 42 digits) contains 4444 as substring.

It is not a weakly prime, because it can be changed into another prime (21317703487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10658851748 + 10658851749.

It is an arithmetic number, because the mean of its divisors is an integer number (10658851749).

Almost surely, 2^21317703497 is an apocalyptic number.

It is an amenable number.

21317703497 is a deficient number, since it is larger than the sum of its proper divisors (1).

21317703497 is an equidigital number, since it uses as much as digits as its factorization.

21317703497 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 222264, while the sum is 44.

The spelling of 21317703497 in words is "twenty-one billion, three hundred seventeen million, seven hundred three thousand, four hundred ninety-seven".