205397794549 has 2 divisors, whose sum is σ = 205397794550. Its totient is φ = 205397794548.

The previous prime is 205397794523. The next prime is 205397794577. The reversal of 205397794549 is 945497793502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144088568100 + 61309226449 = 379590^2 + 247607^2 .

It is a cyclic number.

It is not a de Polignac number, because 205397794549 - 2¹³ = 205397786357 is a prime.

It is a super-2 number, since 2×205397794549² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205397794249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102698897274 + 102698897275.

It is an arithmetic number, because the mean of its divisors is an integer number (102698897275).

Almost surely, 2^205397794549 is an apocalyptic number.

It is an amenable number.

205397794549 is a deficient number, since it is larger than the sum of its proper divisors (1).

205397794549 is an equidigital number, since it uses as much as digits as its factorization.

205397794549 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 85730400, while the sum is 64.

The spelling of 205397794549 in words is "two hundred five billion, three hundred ninety-seven million, seven hundred ninety-four thousand, five hundred forty-nine".