666661519 has 2 divisors, whose sum is σ = 666661520. Its totient is φ = 666661518.

The previous prime is 666661469. The next prime is 666661547. The reversal of 666661519 is 915166666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666661519 - 2⁹ = 666661007 is a prime.

It is a super-2 number, since 2×666661519² = 888875161830774722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666661559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333330759 + 333330760.

It is an arithmetic number, because the mean of its divisors is an integer number (333330760).

Almost surely, 2^666661519 is an apocalyptic number.

666661519 is a deficient number, since it is larger than the sum of its proper divisors (1).

666661519 is an equidigital number, since it uses as much as digits as its factorization.

666661519 is an evil number, because the sum of its binary digits is even.

The product of its digits is 349920, while the sum is 46.

The square root of 666661519 is about 25819.7892903873. The cubic root of 666661519 is about 873.5782162800.

The spelling of 666661519 in words is "six hundred sixty-six million, six hundred sixty-one thousand, five hundred nineteen".