205501649 has 2 divisors, whose sum is σ = 205501650. Its totient is φ = 205501648.

The previous prime is 205501613. The next prime is 205501651. The reversal of 205501649 is 946105502.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 204633025 + 868624 = 14305^2 + 932^2 .

It is a cyclic number.

It is not a de Polignac number, because 205501649 - 2²⁴ = 188724433 is a prime.

Together with 205501651, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (205501679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102750824 + 102750825.

It is an arithmetic number, because the mean of its divisors is an integer number (102750825).

Almost surely, 2^205501649 is an apocalyptic number.

It is an amenable number.

205501649 is a deficient number, since it is larger than the sum of its proper divisors (1).

205501649 is an equidigital number, since it uses as much as digits as its factorization.

205501649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 205501649 is about 14335.3287021958. The cubic root of 205501649 is about 590.1174227649.

The spelling of 205501649 in words is "two hundred five million, five hundred one thousand, six hundred forty-nine".