1665264857 has 2 divisors, whose sum is σ = 1665264858. Its totient is φ = 1665264856.

The previous prime is 1665264847. The next prime is 1665264859. The reversal of 1665264857 is 7584625661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1606727056 + 58537801 = 40084^2 + 7651^2 .

It is a cyclic number.

It is not a de Polignac number, because 1665264857 - 2¹⁶ = 1665199321 is a prime.

Together with 1665264859, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1665264859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832632428 + 832632429.

It is an arithmetic number, because the mean of its divisors is an integer number (832632429).

Almost surely, 2^1665264857 is an apocalyptic number.

It is an amenable number.

1665264857 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665264857 is an equidigital number, since it uses as much as digits as its factorization.

1665264857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2419200, while the sum is 50.

The square root of 1665264857 is about 40807.6568428034. The cubic root of 1665264857 is about 1185.2986024313.

The spelling of 1665264857 in words is "one billion, six hundred sixty-five million, two hundred sixty-four thousand, eight hundred fifty-seven".