1661516611 has 2 divisors, whose sum is σ = 1661516612. Its totient is φ = 1661516610.

The previous prime is 1661516569. The next prime is 1661516621. The reversal of 1661516611 is 1166151661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1661516611 - 2¹⁹ = 1660992323 is a prime.

It is not a weakly prime, because it can be changed into another prime (1661516621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830758305 + 830758306.

It is an arithmetic number, because the mean of its divisors is an integer number (830758306).

Almost surely, 2^1661516611 is an apocalyptic number.

1661516611 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661516611 is an equidigital number, since it uses as much as digits as its factorization.

1661516611 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6480, while the sum is 34.

The square root of 1661516611 is about 40761.7052023097. The cubic root of 1661516611 is about 1184.4086282351.

The spelling of 1661516611 in words is "one billion, six hundred sixty-one million, five hundred sixteen thousand, six hundred eleven".