645810436 has 6 divisors (see below), whose sum is σ = 1130168270. Its totient is φ = 322905216.

The previous prime is 645810427. The next prime is 645810449. The reversal of 645810436 is 634018546.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 440748036 + 205062400 = 20994^2 + 14320^2 .

It is a super-2 number, since 2×645810436² = 834142238493020192, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 645810395 and 645810404.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80726301 + ... + 80726308.

Almost surely, 2^645810436 is an apocalyptic number.

It is an amenable number.

645810436 is a deficient number, since it is larger than the sum of its proper divisors (484357834).

645810436 is a wasteful number, since it uses less digits than its factorization.

645810436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161452613 (or 161452611 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 37.

The square root of 645810436 is about 25412.8006327520. The cubic root of 645810436 is about 864.3739825455.

The spelling of 645810436 in words is "six hundred forty-five million, eight hundred ten thousand, four hundred thirty-six".