393961440655 has 4 divisors (see below), whose sum is σ = 472753728792. Its totient is φ = 315169152520.

The previous prime is 393961440589. The next prime is 393961440659. The reversal of 393961440655 is 556044169393.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 556044169393 = 6469 ⋅85955197.

It is not a de Polignac number, because 393961440655 - 2⁷ = 393961440527 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 393961440596 and 393961440605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393961440659) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39396144061 + ... + 39396144070.

It is an arithmetic number, because the mean of its divisors is an integer number (118188432198).

Almost surely, 2^393961440655 is an apocalyptic number.

393961440655 is a deficient number, since it is larger than the sum of its proper divisors (78792288137).

393961440655 is an equidigital number, since it uses as much as digits as its factorization.

393961440655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78792288136.

The product of its (nonzero) digits is 10497600, while the sum is 55.

The spelling of 393961440655 in words is "three hundred ninety-three billion, nine hundred sixty-one million, four hundred forty thousand, six hundred fifty-five".