1666503257 has 2 divisors, whose sum is σ = 1666503258. Its totient is φ = 1666503256.

The previous prime is 1666503253. The next prime is 1666503277. The reversal of 1666503257 is 7523056661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1257695296 + 408807961 = 35464^2 + 20219^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666503257 - 2² = 1666503253 is a prime.

It is not a weakly prime, because it can be changed into another prime (1666503253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833251628 + 833251629.

It is an arithmetic number, because the mean of its divisors is an integer number (833251629).

Almost surely, 2^1666503257 is an apocalyptic number.

It is an amenable number.

1666503257 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666503257 is an equidigital number, since it uses as much as digits as its factorization.

1666503257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 226800, while the sum is 41.

The square root of 1666503257 is about 40822.8276458160. The cubic root of 1666503257 is about 1185.5923515136.

The spelling of 1666503257 in words is "one billion, six hundred sixty-six million, five hundred three thousand, two hundred fifty-seven".