1518516661 has 2 divisors, whose sum is σ = 1518516662. Its totient is φ = 1518516660.

The previous prime is 1518516641. The next prime is 1518516709. The reversal of 1518516661 is 1666158151.

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., 1484946225 + 33570436 = 38535^2 + 5794^2 .

It is a cyclic number.

It is not a de Polignac number, because 1518516661 - 2⁷ = 1518516533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1518516611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 759258330 + 759258331.

It is an arithmetic number, because the mean of its divisors is an integer number (759258331).

Almost surely, 2^1518516661 is an apocalyptic number.

It is an amenable number.

1518516661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1518516661 is an equidigital number, since it uses as much as digits as its factorization.

1518516661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43200, while the sum is 40.

The square root of 1518516661 is about 38968.1493145364. The cubic root of 1518516661 is about 1149.4052781262.

The spelling of 1518516661 in words is "one billion, five hundred eighteen million, five hundred sixteen thousand, six hundred sixty-one".