645769457 has 4 divisors (see below), whose sum is σ = 652163316. Its totient is φ = 639375600.

The previous prime is 645769451. The next prime is 645769499. The reversal of 645769457 is 754967546.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 273703936 + 372065521 = 16544^2 + 19289^2 .

It is a cyclic number.

It is not a de Polignac number, because 645769457 - 2⁴ = 645769441 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645769399 and 645769408.

It is not an unprimeable number, because it can be changed into a prime (645769451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3196778 + ... + 3196979.

It is an arithmetic number, because the mean of its divisors is an integer number (163040829).

Almost surely, 2^645769457 is an apocalyptic number.

It is an amenable number.

645769457 is a deficient number, since it is larger than the sum of its proper divisors (6393859).

645769457 is a wasteful number, since it uses less digits than its factorization.

645769457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6393858.

The product of its digits is 6350400, while the sum is 53.

The square root of 645769457 is about 25411.9943530609. The cubic root of 645769457 is about 864.3556996105.

The spelling of 645769457 in words is "six hundred forty-five million, seven hundred sixty-nine thousand, four hundred fifty-seven".