660405397 has 2 divisors, whose sum is σ = 660405398. Its totient is φ = 660405396.

The previous prime is 660405331. The next prime is 660405407. The reversal of 660405397 is 793504066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 553613841 + 106791556 = 23529^2 + 10334^2 .

It is a cyclic number.

It is not a de Polignac number, because 660405397 - 2⁷ = 660405269 is a prime.

It is a super-2 number, since 2×660405397² = 872270576773455218, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (660405797) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330202698 + 330202699.

It is an arithmetic number, because the mean of its divisors is an integer number (330202699).

Almost surely, 2^660405397 is an apocalyptic number.

It is an amenable number.

660405397 is a deficient number, since it is larger than the sum of its proper divisors (1).

660405397 is an equidigital number, since it uses as much as digits as its factorization.

660405397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 136080, while the sum is 40.

The square root of 660405397 is about 25698.3539745253. The cubic root of 660405397 is about 870.8369964962.

The spelling of 660405397 in words is "six hundred sixty million, four hundred five thousand, three hundred ninety-seven".