1645071773 has 2 divisors, whose sum is σ = 1645071774. Its totient is φ = 1645071772.

The previous prime is 1645071733. The next prime is 1645071781. The reversal of 1645071773 is 3771705461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1644951364 + 120409 = 40558^2 + 347^2 .

It is a cyclic number.

It is not a de Polignac number, because 1645071773 - 2¹⁴ = 1645055389 is a prime.

It is a super-2 number, since 2×1645071773² = 5412522276642727058, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1645071773.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1645071713) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822535886 + 822535887.

It is an arithmetic number, because the mean of its divisors is an integer number (822535887).

Almost surely, 2^1645071773 is an apocalyptic number.

It is an amenable number.

1645071773 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645071773 is an equidigital number, since it uses as much as digits as its factorization.

1645071773 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 123480, while the sum is 41.

The square root of 1645071773 is about 40559.4843778863. The cubic root of 1645071773 is about 1180.4881091345.

The spelling of 1645071773 in words is "one billion, six hundred forty-five million, seventy-one thousand, seven hundred seventy-three".