665404540394 has 64 divisors (see below), whose sum is σ = 1136930981760. Its totient is φ = 289411584000.

The previous prime is 665404540387. The next prime is 665404540459. The reversal of 665404540394 is 493045404566.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19405637 + ... + 19439895.

It is an arithmetic number, because the mean of its divisors is an integer number (17764546590).

Almost surely, 2^665404540394 is an apocalyptic number.

665404540394 is a deficient number, since it is larger than the sum of its proper divisors (471526441366).

665404540394 is a wasteful number, since it uses less digits than its factorization.

665404540394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34727.

The product of its (nonzero) digits is 6220800, while the sum is 50.

The spelling of 665404540394 in words is "six hundred sixty-five billion, four hundred four million, five hundred forty thousand, three hundred ninety-four".