55278813665 has 4 divisors (see below), whose sum is σ = 66334576404. Its totient is φ = 44223050928.

The previous prime is 55278813661. The next prime is 55278813671. The reversal of 55278813665 is 56631887255.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 26389352704 + 28889460961 = 162448^2 + 169969^2 .

It is a cyclic number.

It is not a de Polignac number, because 55278813665 - 2² = 55278813661 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 55278813665.

It is not an unprimeable number, because it can be changed into a prime (55278813661) 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, 5527881362 + ... + 5527881371.

It is an arithmetic number, because the mean of its divisors is an integer number (16583644101).

Almost surely, 2^55278813665 is an apocalyptic number.

It is an amenable number.

55278813665 is a deficient number, since it is larger than the sum of its proper divisors (11055762739).

55278813665 is a wasteful number, since it uses less digits than its factorization.

55278813665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11055762738.

The product of its digits is 12096000, while the sum is 56.

The spelling of 55278813665 in words is "fifty-five billion, two hundred seventy-eight million, eight hundred thirteen thousand, six hundred sixty-five".