21038000197 has 2 divisors, whose sum is σ = 21038000198. Its totient is φ = 21038000196.

The previous prime is 21038000171. The next prime is 21038000219. The reversal of 21038000197 is 79100083012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20355014241 + 682985956 = 142671^2 + 26134^2 .

It is a cyclic number.

It is not a de Polignac number, because 21038000197 - 2¹⁹ = 21037475909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21038000897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10519000098 + 10519000099.

It is an arithmetic number, because the mean of its divisors is an integer number (10519000099).

Almost surely, 2^21038000197 is an apocalyptic number.

It is an amenable number.

21038000197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21038000197 is an equidigital number, since it uses as much as digits as its factorization.

21038000197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 31.

The spelling of 21038000197 in words is "twenty-one billion, thirty-eight million, one hundred ninety-seven", and thus it is an aban number.