645532369 has 2 divisors, whose sum is σ = 645532370. Its totient is φ = 645532368.

The previous prime is 645532367. The next prime is 645532411. The reversal of 645532369 is 963235546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 583705600 + 61826769 = 24160^2 + 7863^2 .

It is a cyclic number.

It is not a de Polignac number, because 645532369 - 2¹ = 645532367 is a prime.

It is a super-3 number, since 3×645532369³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

Together with 645532367, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (645532361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322766184 + 322766185.

It is an arithmetic number, because the mean of its divisors is an integer number (322766185).

Almost surely, 2^645532369 is an apocalyptic number.

It is an amenable number.

645532369 is a deficient number, since it is larger than the sum of its proper divisors (1).

645532369 is an equidigital number, since it uses as much as digits as its factorization.

645532369 is an evil number, because the sum of its binary digits is even.

The product of its digits is 583200, while the sum is 43.

The square root of 645532369 is about 25407.3290410464. The cubic root of 645532369 is about 864.2499067221.

The spelling of 645532369 in words is "six hundred forty-five million, five hundred thirty-two thousand, three hundred sixty-nine".