1011201661 has 2 divisors, whose sum is σ = 1011201662. Its totient is φ = 1011201660.

The previous prime is 1011201643. The next prime is 1011201673. The reversal of 1011201661 is 1661021101.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 979064100 + 32137561 = 31290^2 + 5669^2 .

It is a cyclic number.

It is not a de Polignac number, because 1011201661 - 2⁵ = 1011201629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1011201461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 505600830 + 505600831.

It is an arithmetic number, because the mean of its divisors is an integer number (505600831).

Almost surely, 2^1011201661 is an apocalyptic number.

It is an amenable number.

1011201661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1011201661 is an equidigital number, since it uses as much as digits as its factorization.

1011201661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 1011201661 is about 31799.3971798209. The cubic root of 1011201661 is about 1003.7200312078.

Adding to 1011201661 its reverse (1661021101), we get a palindrome (2672222762).

The spelling of 1011201661 in words is "one billion, eleven million, two hundred one thousand, six hundred sixty-one".