647545878 has 144 divisors (see below), whose sum is σ = 1819836720. Its totient is φ = 164892672.

The previous prime is 647545867. The next prime is 647545879. The reversal of 647545878 is 878545746.

647545878 is a `hidden beast` number, since 6 + 4 + 7 + 54 + 587 + 8 = 666.

It is a super-2 number, since 2×647545878² = 838631328229581768, which contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647545879) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 283750 + ... + 286022.

It is an arithmetic number, because the mean of its divisors is an integer number (12637755).

Almost surely, 2^647545878 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 647545878, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (909918360).

647545878 is an abundant number, since it is smaller than the sum of its proper divisors (1172290842).

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

647545878 is a wasteful number, since it uses less digits than its factorization.

647545878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2331 (or 2321 counting only the distinct ones).

The product of its digits is 7526400, while the sum is 54.

The square root of 647545878 is about 25446.9227609155. The cubic root of 647545878 is about 865.1475476418.

The spelling of 647545878 in words is "six hundred forty-seven million, five hundred forty-five thousand, eight hundred seventy-eight".