21313670197 has 2 divisors, whose sum is σ = 21313670198. Its totient is φ = 21313670196.

The previous prime is 21313670179. The next prime is 21313670221. The reversal of 21313670197 is 79107631312.

Together with previous prime (21313670179) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21313372081 + 298116 = 145991^2 + 546^2 .

It is a cyclic number.

It is not a de Polignac number, because 21313670197 - 2²³ = 21305281589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21313673197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656835098 + 10656835099.

It is an arithmetic number, because the mean of its divisors is an integer number (10656835099).

Almost surely, 2^21313670197 is an apocalyptic number.

It is an amenable number.

21313670197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21313670197 is an equidigital number, since it uses as much as digits as its factorization.

21313670197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 47628, while the sum is 40.

The spelling of 21313670197 in words is "twenty-one billion, three hundred thirteen million, six hundred seventy thousand, one hundred ninety-seven".