645436756 has 24 divisors (see below), whose sum is σ = 1218528360. Its totient is φ = 298002432.

The previous prime is 645436697. The next prime is 645436829. The reversal of 645436756 is 657634546.

It can be written as a sum of positive squares in 4 ways, for example, as 210714256 + 434722500 = 14516^2 + 20850^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85941 + ... + 93148.

It is an arithmetic number, because the mean of its divisors is an integer number (50772015).

Almost surely, 2^645436756 is an apocalyptic number.

It is an amenable number.

645436756 is a deficient number, since it is larger than the sum of its proper divisors (573091604).

645436756 is a wasteful number, since it uses less digits than its factorization.

645436756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179163 (or 179161 counting only the distinct ones).

The product of its digits is 1814400, while the sum is 46.

The square root of 645436756 is about 25405.4473686255. The cubic root of 645436756 is about 864.2072351689.

The spelling of 645436756 in words is "six hundred forty-five million, four hundred thirty-six thousand, seven hundred fifty-six".