21011202197 has 4 divisors (see below), whose sum is σ = 21073550316. Its totient is φ = 20948854080.

The previous prime is 21011202161. The next prime is 21011202209. The reversal of 21011202197 is 79120211012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14436262801 + 6574939396 = 120151^2 + 81086^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011202197 - 2⁶ = 21011202133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011202697) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31173554 + ... + 31174227.

It is an arithmetic number, because the mean of its divisors is an integer number (5268387579).

Almost surely, 2^21011202197 is an apocalyptic number.

It is an amenable number.

21011202197 is a deficient number, since it is larger than the sum of its proper divisors (62348119).

21011202197 is an equidigital number, since it uses as much as digits as its factorization.

21011202197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62348118.

The product of its (nonzero) digits is 504, while the sum is 26.

The spelling of 21011202197 in words is "twenty-one billion, eleven million, two hundred two thousand, one hundred ninety-seven".