645655661084448 has 216 divisors, whose sum is σ = 2118175291395072. Its totient is φ = 182748992332032.

The previous prime is 645655661084437. The next prime is 645655661084449. The reversal of 645655661084448 is 844480166556546.

645655661084448 is a `hidden beast` number, since 6 + 4 + 5 + 6 + 5 + 566 + 10 + 8 + 4 + 4 + 48 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is not an unprimeable number, because it can be changed into a prime (645655661084449) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 9094561 + ... + 37067807.

It is an arithmetic number, because the mean of its divisors is an integer number (9806367089792).

Almost surely, 2^{645655661084448} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645655661084448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1059087645697536).

645655661084448 is an abundant number, since it is smaller than the sum of its proper divisors (1472519630310624).

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

645655661084448 is a wasteful number, since it uses less digits than its factorization.

645655661084448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27973484 (or 27973366 counting only the distinct ones).

The product of its (nonzero) digits is 2654208000, while the sum is 72.

The spelling of 645655661084448 in words is "six hundred forty-five trillion, six hundred fifty-five billion, six hundred sixty-one million, eighty-four thousand, four hundred forty-eight".