1905165221 has 2 divisors, whose sum is σ = 1905165222. Its totient is φ = 1905165220.

The previous prime is 1905165211. The next prime is 1905165259. The reversal of 1905165221 is 1225615091.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1435576321 + 469588900 = 37889^2 + 21670^2 .

It is a cyclic number.

It is not a de Polignac number, because 1905165221 - 2¹⁰ = 1905164197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1905165211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 952582610 + 952582611.

It is an arithmetic number, because the mean of its divisors is an integer number (952582611).

Almost surely, 2^1905165221 is an apocalyptic number.

It is an amenable number.

1905165221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1905165221 is an equidigital number, since it uses as much as digits as its factorization.

1905165221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 32.

The square root of 1905165221 is about 43648.1983706086. The cubic root of 1905165221 is about 1239.6836734303.

The spelling of 1905165221 in words is "one billion, nine hundred five million, one hundred sixty-five thousand, two hundred twenty-one".