645515648 has 32 divisors (see below), whose sum is σ = 1289328960. Its totient is φ = 321919488.

The previous prime is 645515639. The next prime is 645515657. The reversal of 645515648 is 846515546.

It is a Cunningham number, because it is equal to 25407²-1.

It is an interprime number because it is at equal distance from previous prime (645515639) and next prime (645515657).

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-3 number, since 3×645515648³ (a number of 27 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 645515599 and 645515608.

It is a congruent number.

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 in 3 ways as a sum of consecutive naturals, for example, 44465 + ... + 57167.

It is an arithmetic number, because the mean of its divisors is an integer number (40291530).

Almost surely, 2^645515648 is an apocalyptic number.

It is an amenable number.

645515648 is a deficient number, since it is larger than the sum of its proper divisors (643813312).

645515648 is a wasteful number, since it uses less digits than its factorization.

645515648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13114 (or 13102 counting only the distinct ones).

The product of its digits is 576000, while the sum is 44.

The square root of 645515648 is about 25406.9999803204. Note that the first 4 decimals coincide. The cubic root of 645515648 is about 864.2424445363.

The spelling of 645515648 in words is "six hundred forty-five million, five hundred fifteen thousand, six hundred forty-eight".