645678825120000 has 2700 divisors, whose sum is σ = 2963319422415660. Its totient is φ = 138900013056000.

The previous prime is 645678825119981. The next prime is 645678825120083. The reversal of 645678825120000 is 21528876546.

645678825120000 is a `hidden beast` number, since 6 + 4 + 56 + 78 + 8 + 2 + 512 + 0 + 0 + 0 + 0 = 666.

It can be written as a sum of positive squares in 10 ways, for example, as 282115828060416 + 363562997059584 = 16796304^2 + 19067328^2 .

It is a tau number, because it is divible by the number of its divisors (2700).

It is a super-2 number, since 2×645678825120000² (a number of 30 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 299 ways as a sum of consecutive naturals, for example, 10795650096 + ... + 10795709904.

Almost surely, 2^{645678825120000} is an apocalyptic number.

645678825120000 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645678825120000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1481659711207830).

645678825120000 is an abundant number, since it is smaller than the sum of its proper divisors (2317640597295660).

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

645678825120000 is an equidigital number, since it uses as much as digits as its factorization.

645678825120000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59888 (or 59843 counting only the distinct ones).

The product of its (nonzero) digits is 6451200, while the sum is 54.

The spelling of 645678825120000 in words is "six hundred forty-five trillion, six hundred seventy-eight billion, eight hundred twenty-five million, one hundred twenty thousand".