21112500197 has 2 divisors, whose sum is σ = 21112500198. Its totient is φ = 21112500196.

The previous prime is 21112500187. The next prime is 21112500257. The reversal of 21112500197 is 79100521112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20905111396 + 207388801 = 144586^2 + 14401^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112500197 - 2²⁶ = 21045391333 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21112500187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556250098 + 10556250099.

It is an arithmetic number, because the mean of its divisors is an integer number (10556250099).

Almost surely, 2^21112500197 is an apocalyptic number.

It is an amenable number.

21112500197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112500197 is an equidigital number, since it uses as much as digits as its factorization.

21112500197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1260, while the sum is 29.

The spelling of 21112500197 in words is "twenty-one billion, one hundred twelve million, five hundred thousand, one hundred ninety-seven".