55552781 has 4 divisors (see below), whose sum is σ = 56313852. Its totient is φ = 54791712.

The previous prime is 55552771. The next prime is 55552793. The reversal of 55552781 is 18725555.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18725555 = 5 ⋅3745111.

It can be written as a sum of positive squares in 2 ways, for example, as 18232900 + 37319881 = 4270^2 + 6109^2 .

It is a cyclic number.

It is not a de Polignac number, because 55552781 - 2²² = 51358477 is a prime.

It is a super-2 number, since 2×55552781² = 6172222953667922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55552771) 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, 380426 + ... + 380571.

It is an arithmetic number, because the mean of its divisors is an integer number (14078463).

Almost surely, 2^55552781 is an apocalyptic number.

It is an amenable number.

55552781 is a deficient number, since it is larger than the sum of its proper divisors (761071).

55552781 is an equidigital number, since it uses as much as digits as its factorization.

55552781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 761070.

The product of its digits is 70000, while the sum is 38.

The square root of 55552781 is about 7453.3737998305. The cubic root of 55552781 is about 381.5650619322.

The spelling of 55552781 in words is "fifty-five million, five hundred fifty-two thousand, seven hundred eighty-one".