55640813 has 8 divisors (see below), whose sum is σ = 60351480. Its totient is φ = 51089920.

The previous prime is 55640801. The next prime is 55640857. The reversal of 55640813 is 31804655.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4761124 + 50879689 = 2182^2 + 7133^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 55640813 - 2¹⁸ = 55378669 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 55640813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55640863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39218 + ... + 40611.

It is an arithmetic number, because the mean of its divisors is an integer number (7543935).

Almost surely, 2^55640813 is an apocalyptic number.

It is an amenable number.

55640813 is a deficient number, since it is larger than the sum of its proper divisors (4710667).

55640813 is a wasteful number, since it uses less digits than its factorization.

55640813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79887.

The product of its (nonzero) digits is 14400, while the sum is 32.

The square root of 55640813 is about 7459.2769756860. The cubic root of 55640813 is about 381.7665052425.

The spelling of 55640813 in words is "fifty-five million, six hundred forty thousand, eight hundred thirteen".