1081956661 has 2 divisors, whose sum is σ = 1081956662. Its totient is φ = 1081956660.

The previous prime is 1081956613. The next prime is 1081956671. The reversal of 1081956661 is 1666591801.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 920819025 + 161137636 = 30345^2 + 12694^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1081956661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1081956611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 540978330 + 540978331.

It is an arithmetic number, because the mean of its divisors is an integer number (540978331).

Almost surely, 2^1081956661 is an apocalyptic number.

It is an amenable number.

1081956661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1081956661 is an equidigital number, since it uses as much as digits as its factorization.

1081956661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 43.

The square root of 1081956661 is about 32893.1096280057. The cubic root of 1081956661 is about 1026.6047948017.

The spelling of 1081956661 in words is "one billion, eighty-one million, nine hundred fifty-six thousand, six hundred sixty-one".