21497175313 has 2 divisors, whose sum is σ = 21497175314. Its totient is φ = 21497175312.

The previous prime is 21497175311. The next prime is 21497175341. The reversal of 21497175313 is 31357179412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15241630849 + 6255544464 = 123457^2 + 79092^2 .

It is a cyclic number.

It is not a de Polignac number, because 21497175313 - 2¹ = 21497175311 is a prime.

Together with 21497175311, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21497175313.

It is not a weakly prime, because it can be changed into another prime (21497175311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10748587656 + 10748587657.

It is an arithmetic number, because the mean of its divisors is an integer number (10748587657).

Almost surely, 2^21497175313 is an apocalyptic number.

It is an amenable number.

21497175313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21497175313 is an equidigital number, since it uses as much as digits as its factorization.

21497175313 is an evil number, because the sum of its binary digits is even.

The product of its digits is 158760, while the sum is 43.

The spelling of 21497175313 in words is "twenty-one billion, four hundred ninety-seven million, one hundred seventy-five thousand, three hundred thirteen".