1645712069 has 2 divisors, whose sum is σ = 1645712070. Its totient is φ = 1645712068.

The previous prime is 1645712051. The next prime is 1645712143. The reversal of 1645712069 is 9602175461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1545511969 + 100200100 = 39313^2 + 10010^2 .

It is a cyclic number.

It is not a de Polignac number, because 1645712069 - 2⁸ = 1645711813 is a prime.

It is a super-3 number, since 3×1645712069³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1645712669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822856034 + 822856035.

It is an arithmetic number, because the mean of its divisors is an integer number (822856035).

Almost surely, 2^1645712069 is an apocalyptic number.

It is an amenable number.

1645712069 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645712069 is an equidigital number, since it uses as much as digits as its factorization.

1645712069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90720, while the sum is 41.

The square root of 1645712069 is about 40567.3769055876. The cubic root of 1645712069 is about 1180.6412460741.

The spelling of 1645712069 in words is "one billion, six hundred forty-five million, seven hundred twelve thousand, sixty-nine".