645678436 has 24 divisors (see below), whose sum is σ = 1239820344. Its totient is φ = 292381440.

The previous prime is 645678431. The next prime is 645678457. The reversal of 645678436 is 634876546.

It can be written as a sum of positive squares in 4 ways, for example, as 264257536 + 381420900 = 16256^2 + 19530^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 645678436.

It is not an unprimeable number, because it can be changed into a prime (645678431) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114385 + ... + 119896.

It is an arithmetic number, because the mean of its divisors is an integer number (51659181).

Almost surely, 2^645678436 is an apocalyptic number.

It is an amenable number.

645678436 is a deficient number, since it is larger than the sum of its proper divisors (594141908).

645678436 is a wasteful number, since it uses less digits than its factorization.

645678436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234351 (or 234349 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 49.

The square root of 645678436 is about 25410.2033836803. The cubic root of 645678436 is about 864.3150874819.

The spelling of 645678436 in words is "six hundred forty-five million, six hundred seventy-eight thousand, four hundred thirty-six".