645071757 has 32 divisors (see below), whose sum is σ = 962648064. Its totient is φ = 380880000.

The previous prime is 645071753. The next prime is 645071759. The reversal of 645071757 is 757170546.

It is not a de Polignac number, because 645071757 - 2² = 645071753 is a prime.

It is a super-2 number, since 2×645071757² = 832235143358134098, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645071753) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 388473 + ... + 390129.

It is an arithmetic number, because the mean of its divisors is an integer number (30082752).

Almost surely, 2^645071757 is an apocalyptic number.

It is an amenable number.

645071757 is a deficient number, since it is larger than the sum of its proper divisors (317576307).

645071757 is a wasteful number, since it uses less digits than its factorization.

645071757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1969.

The product of its (nonzero) digits is 205800, while the sum is 42.

The square root of 645071757 is about 25398.2628736691. The cubic root of 645071757 is about 864.0442993726.

The spelling of 645071757 in words is "six hundred forty-five million, seventy-one thousand, seven hundred fifty-seven".