2197205821 has 2 divisors, whose sum is σ = 2197205822. Its totient is φ = 2197205820.

The previous prime is 2197205779. The next prime is 2197205833. The reversal of 2197205821 is 1285027912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2189304100 + 7901721 = 46790^2 + 2811^2 .

It is a cyclic number.

It is not a de Polignac number, because 2197205821 - 2²⁹ = 1660334909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2197205221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1098602910 + 1098602911.

It is an arithmetic number, because the mean of its divisors is an integer number (1098602911).

Almost surely, 2^2197205821 is an apocalyptic number.

It is an amenable number.

2197205821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2197205821 is an equidigital number, since it uses as much as digits as its factorization.

2197205821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20160, while the sum is 37.

The square root of 2197205821 is about 46874.3620863260. The cubic root of 2197205821 is about 1300.0405945903.

The spelling of 2197205821 in words is "two billion, one hundred ninety-seven million, two hundred five thousand, eight hundred twenty-one".