405665356671 has 12 divisors (see below), whose sum is σ = 585968113848. Its totient is φ = 270440320464.

The previous prime is 405665356661. The next prime is 405665356699. The reversal of 405665356671 is 176653566504.

405665356671 is a `hidden beast` number, since 4 + 0 + 5 + 6 + 6 + 5 + 3 + 566 + 71 = 666.

It is not a de Polignac number, because 405665356671 - 2¹⁷ = 405665225599 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405665356601) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 704221 + ... + 1143353.

It is an arithmetic number, because the mean of its divisors is an integer number (48830676154).

Almost surely, 2^405665356671 is an apocalyptic number.

405665356671 is a deficient number, since it is larger than the sum of its proper divisors (180302757177).

405665356671 is a wasteful number, since it uses less digits than its factorization.

405665356671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 541782 (or 541779 counting only the distinct ones).

The product of its (nonzero) digits is 13608000, while the sum is 54.

The spelling of 405665356671 in words is "four hundred five billion, six hundred sixty-five million, three hundred fifty-six thousand, six hundred seventy-one".