71778564 has 144 divisors (see below), whose sum is σ = 217211904. Its totient is φ = 19699200.

The previous prime is 71778533. The next prime is 71778569. The reversal of 71778564 is 46587717.

71778564 is a `hidden beast` number, since 7 + 17 + 78 + 564 = 666.

It is not an unprimeable number, because it can be changed into a prime (71778569) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 375709 + ... + 375899.

It is an arithmetic number, because the mean of its divisors is an integer number (1508416).

Almost surely, 2^71778564 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 71778564, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108605952).

71778564 is an abundant number, since it is smaller than the sum of its proper divisors (145433340).

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

71778564 is a wasteful number, since it uses less digits than its factorization.

71778564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298 (or 293 counting only the distinct ones).

The product of its digits is 329280, while the sum is 45.

The square root of 71778564 is about 8472.2230848816. The cubic root of 71778564 is about 415.5898401222.

The spelling of 71778564 in words is "seventy-one million, seven hundred seventy-eight thousand, five hundred sixty-four".