645785657 has 8 divisors (see below), whose sum is σ = 704751840. Its totient is φ = 586862560.

The previous prime is 645785641. The next prime is 645785663. The reversal of 645785657 is 756587546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645785657 - 2⁴ = 645785641 is a prime.

It is a super-2 number, since 2×645785657² = 834078229573843298, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645785599 and 645785608.

It is not an unprimeable number, because it can be changed into a prime (645785627) 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 7 ways as a sum of consecutive naturals, for example, 26069 + ... + 44397.

It is an arithmetic number, because the mean of its divisors is an integer number (88093980).

Almost surely, 2^645785657 is an apocalyptic number.

It is an amenable number.

645785657 is a deficient number, since it is larger than the sum of its proper divisors (58966183).

645785657 is a wasteful number, since it uses less digits than its factorization.

645785657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21543.

The product of its digits is 7056000, while the sum is 53.

The square root of 645785657 is about 25412.3130981814. The cubic root of 645785657 is about 864.3629273939.

The spelling of 645785657 in words is "six hundred forty-five million, seven hundred eighty-five thousand, six hundred fifty-seven".