55807993 has 4 divisors (see below), whose sum is σ = 56861028. Its totient is φ = 54754960.

The previous prime is 55807981. The next prime is 55808009. The reversal of 55807993 is 39970855.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 39970855 = 5 ⋅7994171.

It can be written as a sum of positive squares in 2 ways, for example, as 32353344 + 23454649 = 5688^2 + 4843^2 .

It is a cyclic number.

It is not a de Polignac number, because 55807993 - 2¹³ = 55799801 is a prime.

It is a super-2 number, since 2×55807993² = 6229064165376098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55807903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 526438 + ... + 526543.

It is an arithmetic number, because the mean of its divisors is an integer number (14215257).

Almost surely, 2^55807993 is an apocalyptic number.

55807993 is a gapful number since it is divisible by the number (53) formed by its first and last digit.

It is an amenable number.

55807993 is a deficient number, since it is larger than the sum of its proper divisors (1053035).

55807993 is a wasteful number, since it uses less digits than its factorization.

55807993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1053034.

The product of its (nonzero) digits is 340200, while the sum is 46.

The square root of 55807993 is about 7470.4747506434. The cubic root of 55807993 is about 382.1484785052.

The spelling of 55807993 in words is "fifty-five million, eight hundred seven thousand, nine hundred ninety-three".