71669354778 has 96 divisors (see below), whose sum is σ = 179847682560. Its totient is φ = 20203812000.

The previous prime is 71669354777. The next prime is 71669354807. The reversal of 71669354778 is 87745396617.

71669354778 is a `hidden beast` number, since 7 + 16 + 6 + 9 + 3 + 547 + 78 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (71669354773) 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, 3373393 + ... + 3394571.

It is an arithmetic number, because the mean of its divisors is an integer number (1873413360).

Almost surely, 2^71669354778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71669354778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89923841280).

71669354778 is an abundant number, since it is smaller than the sum of its proper divisors (108178327782).

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

71669354778 is a wasteful number, since it uses less digits than its factorization.

71669354778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21552 (or 21549 counting only the distinct ones).

The product of its digits is 53343360, while the sum is 63.

The spelling of 71669354778 in words is "seventy-one billion, six hundred sixty-nine million, three hundred fifty-four thousand, seven hundred seventy-eight".