2011665521 has 2 divisors, whose sum is σ = 2011665522. Its totient is φ = 2011665520.

The previous prime is 2011665497. The next prime is 2011665569. The reversal of 2011665521 is 1255661102.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1322340496 + 689325025 = 36364^2 + 26255^2 .

It is a cyclic number.

It is not a de Polignac number, because 2011665521 - 2¹⁰ = 2011664497 is a prime.

It is not a weakly prime, because it can be changed into another prime (2011665421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1005832760 + 1005832761.

It is an arithmetic number, because the mean of its divisors is an integer number (1005832761).

Almost surely, 2^2011665521 is an apocalyptic number.

It is an amenable number.

2011665521 is a deficient number, since it is larger than the sum of its proper divisors (1).

2011665521 is an equidigital number, since it uses as much as digits as its factorization.

2011665521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 2011665521 is about 44851.5944086718. The cubic root of 2011665521 is about 1262.3659085242.

The spelling of 2011665521 in words is "two billion, eleven million, six hundred sixty-five thousand, five hundred twenty-one".