205054638421 has 2 divisors, whose sum is σ = 205054638422. Its totient is φ = 205054638420.

The previous prime is 205054638407. The next prime is 205054638427. The reversal of 205054638421 is 124836450502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 178130423025 + 26924215396 = 422055^2 + 164086^2 .

It is a cyclic number.

It is not a de Polignac number, because 205054638421 - 2¹³ = 205054630229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205054638427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102527319210 + 102527319211.

It is an arithmetic number, because the mean of its divisors is an integer number (102527319211).

Almost surely, 2^205054638421 is an apocalyptic number.

It is an amenable number.

205054638421 is a deficient number, since it is larger than the sum of its proper divisors (1).

205054638421 is an equidigital number, since it uses as much as digits as its factorization.

205054638421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 230400, while the sum is 40.

The spelling of 205054638421 in words is "two hundred five billion, fifty-four million, six hundred thirty-eight thousand, four hundred twenty-one".