205422243021 has 8 divisors (see below), whose sum is σ = 304329248960. Its totient is φ = 136948161996.

The previous prime is 205422242999. The next prime is 205422243041. The reversal of 205422243021 is 120342224502.

205422243021 is a `hidden beast` number, since 2 + 0 + 5 + 4 + 222 + 430 + 2 + 1 = 666.

It is a de Polignac number, because none of the positive numbers 2^k-205422243021 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 7608231223 = 205422243021 / (2 + 0 + 5 + 4 + 2 + 2 + 2 + 4 + 3 + 0 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205422243041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3804115585 + ... + 3804115638.

It is an arithmetic number, because the mean of its divisors is an integer number (38041156120).

Almost surely, 2^205422243021 is an apocalyptic number.

It is an amenable number.

205422243021 is a deficient number, since it is larger than the sum of its proper divisors (98907005939).

205422243021 is an equidigital number, since it uses as much as digits as its factorization.

205422243021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7608231232 (or 7608231226 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 27.

Adding to 205422243021 its reverse (120342224502), we get a palindrome (325764467523).

The spelling of 205422243021 in words is "two hundred five billion, four hundred twenty-two million, two hundred forty-three thousand, twenty-one".