645677320 has 16 divisors (see below), whose sum is σ = 1452774060. Its totient is φ = 258270912.

The previous prime is 645677317. The next prime is 645677341. The reversal of 645677320 is 23776546.

It can be written as a sum of positive squares in 2 ways, for example, as 635140804 + 10536516 = 25202^2 + 3246^2 .

It is a Harshad number since it is a multiple of its sum of digits (40), and also a Moran number because the ratio is a prime number: 16141933 = 645677320 / (6 + 4 + 5 + 6 + 7 + 7 + 3 + 2 + 0).

It is a zygodrome in base 7.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8070927 + ... + 8071006.

Almost surely, 2^645677320 is an apocalyptic number.

It is an amenable number.

645677320 is an abundant number, since it is smaller than the sum of its proper divisors (807096740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645677320 is a wasteful number, since it uses less digits than its factorization.

645677320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16141944 (or 16141940 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 40.

The square root of 645677320 is about 25410.1814239883. The cubic root of 645677320 is about 864.3145895167.

The spelling of 645677320 in words is "six hundred forty-five million, six hundred seventy-seven thousand, three hundred twenty".