405665686278 has 12 divisors (see below), whose sum is σ = 878942320308. Its totient is φ = 135221895420.

The previous prime is 405665686277. The next prime is 405665686339. The reversal of 405665686278 is 872686566504.

It is a happy number.

405665686278 is a `hidden beast` number, since 4 + 0 + 5 + 6 + 6 + 568 + 62 + 7 + 8 = 666.

405665686278 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405665686277) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11268491268 + ... + 11268491303.

It is an arithmetic number, because the mean of its divisors is an integer number (73245193359).

Almost surely, 2^405665686278 is an apocalyptic number.

405665686278 is an abundant number, since it is smaller than the sum of its proper divisors (473276634030).

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

405665686278 is a wasteful number, since it uses less digits than its factorization.

405665686278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22536982579 (or 22536982576 counting only the distinct ones).

The product of its (nonzero) digits is 116121600, while the sum is 63.

The spelling of 405665686278 in words is "four hundred five billion, six hundred sixty-five million, six hundred eighty-six thousand, two hundred seventy-eight".