64578015720 has 64 divisors (see below), whose sum is σ = 215260056000. Its totient is φ = 17220803904.

The previous prime is 64578015713. The next prime is 64578015721. The reversal of 64578015720 is 2751087546.

64578015720 is a `hidden beast` number, since 6 + 4 + 5 + 78 + 0 + 1 + 572 + 0 = 666.

It is a super-2 number, since 2×64578015720² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (64578015721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29896150 + ... + 29898309.

It is an arithmetic number, because the mean of its divisors is an integer number (3363438375).

Almost surely, 2^64578015720 is an apocalyptic number.

64578015720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

64578015720 is an abundant number, since it is smaller than the sum of its proper divisors (150682040280).

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

64578015720 is a wasteful number, since it uses less digits than its factorization.

64578015720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59794479 (or 59794469 counting only the distinct ones).

The product of its (nonzero) digits is 470400, while the sum is 45.

The spelling of 64578015720 in words is "sixty-four billion, five hundred seventy-eight million, fifteen thousand, seven hundred twenty".