21020200197 has 4 divisors (see below), whose sum is σ = 28026933600. Its totient is φ = 14013466796.

The previous prime is 21020200193. The next prime is 21020200199. The reversal of 21020200197 is 79100202012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21020200197 - 2² = 21020200193 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020200193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3503366697 + ... + 3503366702.

It is an arithmetic number, because the mean of its divisors is an integer number (7006733400).

Almost surely, 2^21020200197 is an apocalyptic number.

It is an amenable number.

21020200197 is a deficient number, since it is larger than the sum of its proper divisors (7006733403).

21020200197 is an equidigital number, since it uses as much as digits as its factorization.

21020200197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7006733402.

The product of its (nonzero) digits is 504, while the sum is 24.

The spelling of 21020200197 in words is "twenty-one billion, twenty million, two hundred thousand, one hundred ninety-seven".