66405404256 has 48 divisors (see below), whose sum is σ = 176702070384. Its totient is φ = 21831911424.

The previous prime is 66405404249. The next prime is 66405404269. The reversal of 66405404256 is 65240450466.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4730821 + ... + 4744836.

It is an arithmetic number, because the mean of its divisors is an integer number (3681293133).

Almost surely, 2^66405404256 is an apocalyptic number.

It is an amenable number.

66405404256 is an abundant number, since it is smaller than the sum of its proper divisors (110296666128).

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

66405404256 is a wasteful number, since it uses less digits than its factorization.

66405404256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9475743 (or 9475735 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 42.

The spelling of 66405404256 in words is "sixty-six billion, four hundred five million, four hundred four thousand, two hundred fifty-six".